feat: add frontend case list, detail, and creation pages (Phase 1F)

- Case list page (/cases) with search, status/type filters, status badges
- Case creation page (/cases/new) with reusable CaseForm component
- Case detail page (/cases/[id]) with tabs: Timeline, Deadlines, Documents, Parties
- CaseTimeline component for chronological case_events display
- PartyList component with inline party CRUD (add/delete)
- Updated sidebar navigation to route to /cases

frontend/src/app/(app)/cases/[id]/page.tsx

@@ -0,0 +1,267 @@
+"use client";
+
+import { useQuery } from "@tanstack/react-query";
+import { useParams } from "next/navigation";
+import { api } from "@/lib/api";
+import type { Case, CaseEvent, Party, Deadline, Document } from "@/lib/types";
+import { CaseTimeline } from "@/components/cases/CaseTimeline";
+import { PartyList } from "@/components/cases/PartyList";
+import { ArrowLeft, Clock, FileText, Users, Activity } from "lucide-react";
+import { format } from "date-fns";
+import { de } from "date-fns/locale";
+import Link from "next/link";
+import { useState } from "react";
+
+interface CaseDetail extends Case {
+  parties: Party[];
+  recent_events: CaseEvent[];
+  deadlines_count: number;
+}
+
+const STATUS_BADGE: Record<string, string> = {
+  active: "bg-emerald-50 text-emerald-700",
+  pending: "bg-amber-50 text-amber-700",
+  closed: "bg-neutral-100 text-neutral-600",
+  archived: "bg-neutral-100 text-neutral-400",
+};
+
+const TABS = [
+  { key: "timeline", label: "Verlauf", icon: Activity },
+  { key: "deadlines", label: "Fristen", icon: Clock },
+  { key: "documents", label: "Dokumente", icon: FileText },
+  { key: "parties", label: "Parteien", icon: Users },
+] as const;
+
+type TabKey = (typeof TABS)[number]["key"];
+
+export default function CaseDetailPage() {
+  const { id } = useParams<{ id: string }>();
+  const [activeTab, setActiveTab] = useState<TabKey>("timeline");
+
+  const { data: caseDetail, isLoading } = useQuery({
+    queryKey: ["case", id],
+    queryFn: () => api.get<CaseDetail>(`/cases/${id}`),
+  });
+
+  const { data: deadlinesData } = useQuery({
+    queryKey: ["case-deadlines", id],
+    queryFn: () =>
+      api.get<{ deadlines: Deadline[]; total: number }>(
+        `/deadlines?case_id=${id}`,
+      ),
+    enabled: activeTab === "deadlines",
+  });
+
+  const { data: documentsData } = useQuery({
+    queryKey: ["case-documents", id],
+    queryFn: () => api.get<Document[]>(`/cases/${id}/documents`),
+    enabled: activeTab === "documents",
+  });
+
+  if (isLoading) {
+    return (
+      <div className="py-12 text-center text-sm text-neutral-400">
+        Laden...
+      </div>
+    );
+  }
+
+  if (!caseDetail) {
+    return (
+      <div className="py-12 text-center text-sm text-neutral-400">
+        Akte nicht gefunden.
+      </div>
+    );
+  }
+
+  const deadlines = deadlinesData?.deadlines ?? [];
+  const documents = documentsData ?? [];
+
+  return (
+    <div>
+      <Link
+        href="/cases"
+        className="mb-4 inline-flex items-center gap-1 text-sm text-neutral-500 hover:text-neutral-700"
+      >
+        <ArrowLeft className="h-3.5 w-3.5" />
+        Zuruck zu Akten
+      </Link>
+
+      <div className="flex items-start justify-between">
+        <div>
+          <div className="flex items-center gap-3">
+            <h1 className="text-lg font-semibold text-neutral-900">
+              {caseDetail.title}
+            </h1>
+            <span
+              className={`inline-block rounded-full px-2 py-0.5 text-xs font-medium ${STATUS_BADGE[caseDetail.status] ?? "bg-neutral-100 text-neutral-500"}`}
+            >
+              {caseDetail.status}
+            </span>
+          </div>
+          <div className="mt-1 flex gap-4 text-sm text-neutral-500">
+            <span>Az. {caseDetail.case_number}</span>
+            {caseDetail.case_type && <span>{caseDetail.case_type}</span>}
+            {caseDetail.court && <span>{caseDetail.court}</span>}
+            {caseDetail.court_ref && <span>({caseDetail.court_ref})</span>}
+          </div>
+        </div>
+        <div className="text-right text-xs text-neutral-400">
+          <p>
+            Erstellt:{" "}
+            {format(new Date(caseDetail.created_at), "d. MMM yyyy", {
+              locale: de,
+            })}
+          </p>
+          <p>
+            Aktualisiert:{" "}
+            {format(new Date(caseDetail.updated_at), "d. MMM yyyy", {
+              locale: de,
+            })}
+          </p>
+        </div>
+      </div>
+
+      {caseDetail.ai_summary && (
+        <div className="mt-4 rounded-md border border-blue-100 bg-blue-50 px-4 py-3 text-sm text-blue-800">
+          {caseDetail.ai_summary}
+        </div>
+      )}
+
+      <div className="mt-6 border-b border-neutral-200">
+        <nav className="-mb-px flex gap-4">
+          {TABS.map((tab) => (
+            <button
+              key={tab.key}
+              onClick={() => setActiveTab(tab.key)}
+              className={`inline-flex items-center gap-1.5 border-b-2 px-1 pb-2.5 text-sm font-medium transition-colors ${
+                activeTab === tab.key
+                  ? "border-neutral-900 text-neutral-900"
+                  : "border-transparent text-neutral-400 hover:text-neutral-600"
+              }`}
+            >
+              <tab.icon className="h-4 w-4" />
+              {tab.label}
+              {tab.key === "deadlines" && caseDetail.deadlines_count > 0 && (
+                <span className="ml-1 rounded-full bg-neutral-100 px-1.5 py-0.5 text-xs text-neutral-500">
+                  {caseDetail.deadlines_count}
+                </span>
+              )}
+              {tab.key === "parties" && caseDetail.parties.length > 0 && (
+                <span className="ml-1 rounded-full bg-neutral-100 px-1.5 py-0.5 text-xs text-neutral-500">
+                  {caseDetail.parties.length}
+                </span>
+              )}
+            </button>
+          ))}
+        </nav>
+      </div>
+
+      <div className="mt-6">
+        {activeTab === "timeline" && (
+          <CaseTimeline events={caseDetail.recent_events ?? []} />
+        )}
+
+        {activeTab === "deadlines" && (
+          <DeadlinesList deadlines={deadlines} />
+        )}
+
+        {activeTab === "documents" && (
+          <DocumentsList documents={documents} />
+        )}
+
+        {activeTab === "parties" && (
+          <PartyList caseId={id} parties={caseDetail.parties ?? []} />
+        )}
+      </div>
+    </div>
+  );
+}
+
+function DeadlinesList({ deadlines }: { deadlines: Deadline[] }) {
+  if (deadlines.length === 0) {
+    return (
+      <p className="py-8 text-center text-sm text-neutral-400">
+        Keine Fristen vorhanden.
+      </p>
+    );
+  }
+
+  const DEADLINE_STATUS: Record<string, string> = {
+    pending: "bg-amber-50 text-amber-700",
+    completed: "bg-emerald-50 text-emerald-700",
+    overdue: "bg-red-50 text-red-700",
+  };
+
+  return (
+    <div className="space-y-2">
+      {deadlines.map((d) => (
+        <div
+          key={d.id}
+          className="flex items-center justify-between rounded-md border border-neutral-200 bg-white px-4 py-3"
+        >
+          <div>
+            <p className="text-sm font-medium text-neutral-900">{d.title}</p>
+            {d.description && (
+              <p className="mt-0.5 text-sm text-neutral-500">
+                {d.description}
+              </p>
+            )}
+          </div>
+          <div className="flex items-center gap-3">
+            <span
+              className={`rounded-full px-2 py-0.5 text-xs font-medium ${DEADLINE_STATUS[d.status] ?? "bg-neutral-100 text-neutral-500"}`}
+            >
+              {d.status}
+            </span>
+            <span className="text-sm text-neutral-500">
+              {format(new Date(d.due_date), "d. MMM yyyy", { locale: de })}
+            </span>
+          </div>
+        </div>
+      ))}
+    </div>
+  );
+}
+
+function DocumentsList({ documents }: { documents: Document[] }) {
+  if (documents.length === 0) {
+    return (
+      <p className="py-8 text-center text-sm text-neutral-400">
+        Keine Dokumente vorhanden.
+      </p>
+    );
+  }
+
+  return (
+    <div className="space-y-2">
+      {documents.map((doc) => (
+        <div
+          key={doc.id}
+          className="flex items-center justify-between rounded-md border border-neutral-200 bg-white px-4 py-3"
+        >
+          <div className="flex items-center gap-3">
+            <FileText className="h-4 w-4 text-neutral-400" />
+            <div>
+              <p className="text-sm font-medium text-neutral-900">
+                {doc.title}
+              </p>
+              <div className="flex gap-2 text-xs text-neutral-400">
+                {doc.doc_type && <span>{doc.doc_type}</span>}
+                {doc.file_size && (
+                  <span>{(doc.file_size / 1024).toFixed(0)} KB</span>
+                )}
+              </div>
+            </div>
+          </div>
+          <a
+            href={`/api/documents/${doc.id}`}
+            className="text-sm text-neutral-500 hover:text-neutral-700"
+          >
+            Herunterladen
+          </a>
+        </div>
+      ))}
+    </div>
+  );
+}

frontend/src/app/(app)/cases/new/page.tsx

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+"use client";
+
+import { useMutation, useQueryClient } from "@tanstack/react-query";
+import { useRouter } from "next/navigation";
+import { toast } from "sonner";
+import { api } from "@/lib/api";
+import type { Case } from "@/lib/types";
+import { CaseForm, type CaseFormData } from "@/components/cases/CaseForm";
+import { ArrowLeft } from "lucide-react";
+import Link from "next/link";
+
+export default function NewCasePage() {
+  const router = useRouter();
+  const queryClient = useQueryClient();
+
+  const mutation = useMutation({
+    mutationFn: (data: CaseFormData) => api.post<Case>("/cases", data),
+    onSuccess: (created) => {
+      queryClient.invalidateQueries({ queryKey: ["cases"] });
+      toast.success("Akte angelegt");
+      router.push(`/cases/${created.id}`);
+    },
+    onError: () => {
+      toast.error("Fehler beim Anlegen der Akte");
+    },
+  });
+
+  return (
+    <div className="mx-auto max-w-2xl">
+      <Link
+        href="/cases"
+        className="mb-4 inline-flex items-center gap-1 text-sm text-neutral-500 hover:text-neutral-700"
+      >
+        <ArrowLeft className="h-3.5 w-3.5" />
+        Zuruck zu Akten
+      </Link>
+      <h1 className="text-lg font-semibold text-neutral-900">Neue Akte</h1>
+      <p className="mt-0.5 text-sm text-neutral-500">
+        Neue Akte im System anlegen
+      </p>
+      <div className="mt-6 rounded-md border border-neutral-200 bg-white p-6">
+        <CaseForm
+          onSubmit={(data) => mutation.mutate(data)}
+          isSubmitting={mutation.isPending}
+        />
+      </div>
+    </div>
+  );
+}

frontend/src/app/(app)/cases/page.tsx

@@ -0,0 +1,172 @@
+"use client";
+
+import { useQuery } from "@tanstack/react-query";
+import { api } from "@/lib/api";
+import type { Case } from "@/lib/types";
+import Link from "next/link";
+import { useSearchParams, useRouter } from "next/navigation";
+import { Plus, Search } from "lucide-react";
+import { useState } from "react";
+
+const STATUS_OPTIONS = [
+  { value: "", label: "Alle Status" },
+  { value: "active", label: "Aktiv" },
+  { value: "pending", label: "Anhangig" },
+  { value: "closed", label: "Geschlossen" },
+  { value: "archived", label: "Archiviert" },
+];
+
+const TYPE_OPTIONS = [
+  { value: "", label: "Alle Typen" },
+  { value: "INF", label: "Verletzungsklage" },
+  { value: "REV", label: "Widerruf" },
+  { value: "CCR", label: "Einstweilige Verfugung" },
+  { value: "APP", label: "Berufung" },
+  { value: "PI", label: "Vorlaufiger Rechtsschutz" },
+  { value: "ZPO_CIVIL", label: "ZPO Zivilverfahren" },
+];
+
+const STATUS_BADGE: Record<string, string> = {
+  active: "bg-emerald-50 text-emerald-700",
+  pending: "bg-amber-50 text-amber-700",
+  closed: "bg-neutral-100 text-neutral-600",
+  archived: "bg-neutral-100 text-neutral-400",
+};
+
+export default function CasesPage() {
+  const router = useRouter();
+  const searchParams = useSearchParams();
+
+  const [search, setSearch] = useState(searchParams.get("search") ?? "");
+  const [status, setStatus] = useState(searchParams.get("status") ?? "");
+  const [type, setType] = useState(searchParams.get("type") ?? "");
+
+  const { data, isLoading } = useQuery({
+    queryKey: ["cases", { search, status, type }],
+    queryFn: () => {
+      const params = new URLSearchParams();
+      if (search) params.set("search", search);
+      if (status) params.set("status", status);
+      if (type) params.set("type", type);
+      params.set("limit", "50");
+      const qs = params.toString();
+      return api.get<{ cases: Case[]; total: number }>(
+        `/cases${qs ? `?${qs}` : ""}`,
+      );
+    },
+  });
+
+  const cases = data?.cases ?? [];
+
+  return (
+    <div>
+      <div className="flex items-center justify-between">
+        <div>
+          <h1 className="text-lg font-semibold text-neutral-900">Akten</h1>
+          <p className="mt-0.5 text-sm text-neutral-500">
+            {data ? `${data.total} Akten` : "Laden..."}
+          </p>
+        </div>
+        <Link
+          href="/cases/new"
+          className="inline-flex items-center gap-1.5 rounded-md bg-neutral-900 px-3 py-1.5 text-sm font-medium text-white hover:bg-neutral-800"
+        >
+          <Plus className="h-4 w-4" />
+          Neue Akte
+        </Link>
+      </div>
+
+      <div className="mt-4 flex items-center gap-3">
+        <div className="relative flex-1">
+          <Search className="absolute left-2.5 top-1/2 h-4 w-4 -translate-y-1/2 text-neutral-400" />
+          <input
+            type="text"
+            placeholder="Suchen nach Aktenzeichen, Titel..."
+            value={search}
+            onChange={(e) => setSearch(e.target.value)}
+            className="w-full rounded-md border border-neutral-200 bg-white py-1.5 pl-9 pr-3 text-sm outline-none focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400"
+          />
+        </div>
+        <select
+          value={status}
+          onChange={(e) => setStatus(e.target.value)}
+          className="rounded-md border border-neutral-200 bg-white px-2.5 py-1.5 text-sm outline-none focus:border-neutral-400"
+        >
+          {STATUS_OPTIONS.map((o) => (
+            <option key={o.value} value={o.value}>
+              {o.label}
+            </option>
+          ))}
+        </select>
+        <select
+          value={type}
+          onChange={(e) => setType(e.target.value)}
+          className="rounded-md border border-neutral-200 bg-white px-2.5 py-1.5 text-sm outline-none focus:border-neutral-400"
+        >
+          {TYPE_OPTIONS.map((o) => (
+            <option key={o.value} value={o.value}>
+              {o.label}
+            </option>
+          ))}
+        </select>
+      </div>
+
+      <div className="mt-4">
+        {isLoading ? (
+          <div className="py-12 text-center text-sm text-neutral-400">
+            Laden...
+          </div>
+        ) : cases.length === 0 ? (
+          <div className="py-12 text-center text-sm text-neutral-400">
+            Keine Akten gefunden.
+          </div>
+        ) : (
+          <div className="overflow-hidden rounded-md border border-neutral-200 bg-white">
+            <table className="w-full text-sm">
+              <thead>
+                <tr className="border-b border-neutral-100 text-left text-xs font-medium uppercase tracking-wider text-neutral-400">
+                  <th className="px-4 py-2.5">Aktenzeichen</th>
+                  <th className="px-4 py-2.5">Titel</th>
+                  <th className="px-4 py-2.5">Typ</th>
+                  <th className="px-4 py-2.5">Gericht</th>
+                  <th className="px-4 py-2.5">Status</th>
+                  <th className="px-4 py-2.5">Erstellt</th>
+                </tr>
+              </thead>
+              <tbody className="divide-y divide-neutral-100">
+                {cases.map((c) => (
+                  <tr
+                    key={c.id}
+                    onClick={() => router.push(`/cases/${c.id}`)}
+                    className="cursor-pointer hover:bg-neutral-50"
+                  >
+                    <td className="px-4 py-2.5 font-medium text-neutral-900">
+                      {c.case_number}
+                    </td>
+                    <td className="px-4 py-2.5 text-neutral-700">{c.title}</td>
+                    <td className="px-4 py-2.5 text-neutral-500">
+                      {c.case_type ?? "-"}
+                    </td>
+                    <td className="px-4 py-2.5 text-neutral-500">
+                      {c.court ?? "-"}
+                    </td>
+                    <td className="px-4 py-2.5">
+                      <span
+                        className={`inline-block rounded-full px-2 py-0.5 text-xs font-medium ${STATUS_BADGE[c.status] ?? "bg-neutral-100 text-neutral-500"}`}
+                      >
+                        {c.status}
+                      </span>
+                    </td>
+                    <td className="px-4 py-2.5 text-neutral-400">
+                      {new Date(c.created_at).toLocaleDateString("de-DE")}
+                    </td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}

frontend/src/components/cases/CaseForm.tsx

@@ -0,0 +1,165 @@
+"use client";
+
+import { useState } from "react";
+
+const TYPE_OPTIONS = [
+  { value: "", label: "-- Typ wahlen --" },
+  { value: "INF", label: "Verletzungsklage (INF)" },
+  { value: "REV", label: "Widerruf (REV)" },
+  { value: "CCR", label: "Einstweilige Verfugung (CCR)" },
+  { value: "APP", label: "Berufung (APP)" },
+  { value: "PI", label: "Vorlaufiger Rechtsschutz (PI)" },
+  { value: "ZPO_CIVIL", label: "ZPO Zivilverfahren" },
+];
+
+export interface CaseFormData {
+  case_number: string;
+  title: string;
+  case_type?: string;
+  court?: string;
+  court_ref?: string;
+  status: string;
+}
+
+interface CaseFormProps {
+  initialData?: Partial<CaseFormData>;
+  onSubmit: (data: CaseFormData) => void;
+  isSubmitting?: boolean;
+  submitLabel?: string;
+}
+
+export function CaseForm({
+  initialData,
+  onSubmit,
+  isSubmitting,
+  submitLabel = "Akte anlegen",
+}: CaseFormProps) {
+  const [form, setForm] = useState<CaseFormData>({
+    case_number: initialData?.case_number ?? "",
+    title: initialData?.title ?? "",
+    case_type: initialData?.case_type ?? "",
+    court: initialData?.court ?? "",
+    court_ref: initialData?.court_ref ?? "",
+    status: initialData?.status ?? "active",
+  });
+
+  function handleSubmit(e: React.FormEvent) {
+    e.preventDefault();
+    const data: CaseFormData = {
+      ...form,
+      case_type: form.case_type || undefined,
+      court: form.court || undefined,
+      court_ref: form.court_ref || undefined,
+    };
+    onSubmit(data);
+  }
+
+  function update(field: keyof CaseFormData, value: string) {
+    setForm((prev) => ({ ...prev, [field]: value }));
+  }
+
+  const inputClass =
+    "w-full rounded-md border border-neutral-200 bg-white px-3 py-1.5 text-sm outline-none focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400";
+
+  return (
+    <form onSubmit={handleSubmit} className="space-y-4">
+      <div className="grid grid-cols-2 gap-4">
+        <div>
+          <label className="mb-1 block text-sm font-medium text-neutral-700">
+            Aktenzeichen *
+          </label>
+          <input
+            type="text"
+            required
+            value={form.case_number}
+            onChange={(e) => update("case_number", e.target.value)}
+            placeholder="z.B. 2026/001"
+            className={inputClass}
+          />
+        </div>
+        <div>
+          <label className="mb-1 block text-sm font-medium text-neutral-700">
+            Status
+          </label>
+          <select
+            value={form.status}
+            onChange={(e) => update("status", e.target.value)}
+            className={inputClass}
+          >
+            <option value="active">Aktiv</option>
+            <option value="pending">Anhangig</option>
+            <option value="closed">Geschlossen</option>
+          </select>
+        </div>
+      </div>
+
+      <div>
+        <label className="mb-1 block text-sm font-medium text-neutral-700">
+          Titel *
+        </label>
+        <input
+          type="text"
+          required
+          value={form.title}
+          onChange={(e) => update("title", e.target.value)}
+          placeholder="Bezeichnung der Akte"
+          className={inputClass}
+        />
+      </div>
+
+      <div className="grid grid-cols-2 gap-4">
+        <div>
+          <label className="mb-1 block text-sm font-medium text-neutral-700">
+            Verfahrensart
+          </label>
+          <select
+            value={form.case_type}
+            onChange={(e) => update("case_type", e.target.value)}
+            className={inputClass}
+          >
+            {TYPE_OPTIONS.map((o) => (
+              <option key={o.value} value={o.value}>
+                {o.label}
+              </option>
+            ))}
+          </select>
+        </div>
+        <div>
+          <label className="mb-1 block text-sm font-medium text-neutral-700">
+            Gericht
+          </label>
+          <input
+            type="text"
+            value={form.court}
+            onChange={(e) => update("court", e.target.value)}
+            placeholder="z.B. UPC Munich Central Division"
+            className={inputClass}
+          />
+        </div>
+      </div>
+
+      <div>
+        <label className="mb-1 block text-sm font-medium text-neutral-700">
+          Gerichtliches Aktenzeichen
+        </label>
+        <input
+          type="text"
+          value={form.court_ref}
+          onChange={(e) => update("court_ref", e.target.value)}
+          placeholder="z.B. UPC_CFI_123/2026"
+          className={inputClass}
+        />
+      </div>
+
+      <div className="flex justify-end pt-2">
+        <button
+          type="submit"
+          disabled={isSubmitting}
+          className="rounded-md bg-neutral-900 px-4 py-1.5 text-sm font-medium text-white hover:bg-neutral-800 disabled:opacity-50"
+        >
+          {isSubmitting ? "Speichern..." : submitLabel}
+        </button>
+      </div>
+    </form>
+  );
+}

frontend/src/components/cases/CaseTimeline.tsx

@@ -0,0 +1,60 @@
+"use client";
+
+import type { CaseEvent } from "@/lib/types";
+import { format } from "date-fns";
+import { de } from "date-fns/locale";
+
+const EVENT_ICONS: Record<string, string> = {
+  case_created: "bg-emerald-500",
+  status_changed: "bg-amber-500",
+  party_added: "bg-blue-500",
+  case_archived: "bg-neutral-400",
+  document_uploaded: "bg-violet-500",
+  deadline_created: "bg-red-500",
+};
+
+interface CaseTimelineProps {
+  events: CaseEvent[];
+}
+
+export function CaseTimeline({ events }: CaseTimelineProps) {
+  if (events.length === 0) {
+    return (
+      <p className="py-8 text-center text-sm text-neutral-400">
+        Keine Ereignisse vorhanden.
+      </p>
+    );
+  }
+
+  return (
+    <div className="relative space-y-0">
+      {events.map((event, i) => (
+        <div key={event.id} className="relative flex gap-3 pb-6">
+          {i < events.length - 1 && (
+            <div className="absolute left-[7px] top-4 h-full w-px bg-neutral-200" />
+          )}
+          <div
+            className={`mt-1 h-[15px] w-[15px] shrink-0 rounded-full border-2 border-white ${EVENT_ICONS[event.event_type ?? ""] ?? "bg-neutral-300"}`}
+          />
+          <div className="min-w-0 flex-1">
+            <p className="text-sm font-medium text-neutral-900">
+              {event.title}
+            </p>
+            {event.description && (
+              <p className="mt-0.5 text-sm text-neutral-500">
+                {event.description}
+              </p>
+            )}
+            <p className="mt-1 text-xs text-neutral-400">
+              {format(
+                new Date(event.event_date ?? event.created_at),
+                "d. MMM yyyy, HH:mm",
+                { locale: de },
+              )}
+            </p>
+          </div>
+        </div>
+      ))}
+    </div>
+  );
+}

frontend/src/components/cases/PartyList.tsx

@@ -0,0 +1,182 @@
+"use client";
+
+import { useMutation, useQueryClient } from "@tanstack/react-query";
+import { useState } from "react";
+import { toast } from "sonner";
+import { api } from "@/lib/api";
+import type { Party } from "@/lib/types";
+import { Plus, Trash2, X } from "lucide-react";
+
+interface PartyListProps {
+  caseId: string;
+  parties: Party[];
+}
+
+interface PartyFormData {
+  name: string;
+  role: string;
+  representative: string;
+}
+
+const ROLE_OPTIONS = [
+  "Klager",
+  "Beklagter",
+  "Nebenintervenient",
+  "Patentinhaber",
+  "Streithelfer",
+];
+
+export function PartyList({ caseId, parties }: PartyListProps) {
+  const queryClient = useQueryClient();
+  const [showForm, setShowForm] = useState(false);
+  const [form, setForm] = useState<PartyFormData>({
+    name: "",
+    role: "",
+    representative: "",
+  });
+
+  const addMutation = useMutation({
+    mutationFn: (data: PartyFormData) =>
+      api.post<Party>(`/cases/${caseId}/parties`, {
+        name: data.name,
+        role: data.role || undefined,
+        representative: data.representative || undefined,
+      }),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["case", caseId] });
+      toast.success("Partei hinzugefugt");
+      setShowForm(false);
+      setForm({ name: "", role: "", representative: "" });
+    },
+    onError: () => toast.error("Fehler beim Hinzufugen"),
+  });
+
+  const deleteMutation = useMutation({
+    mutationFn: (partyId: string) => api.delete(`/parties/${partyId}`),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ["case", caseId] });
+      toast.success("Partei entfernt");
+    },
+    onError: () => toast.error("Fehler beim Entfernen"),
+  });
+
+  const inputClass =
+    "w-full rounded-md border border-neutral-200 bg-white px-3 py-1.5 text-sm outline-none focus:border-neutral-400 focus:ring-1 focus:ring-neutral-400";
+
+  return (
+    <div>
+      <div className="flex items-center justify-between">
+        <h3 className="text-sm font-medium text-neutral-700">
+          Parteien ({parties.length})
+        </h3>
+        {!showForm && (
+          <button
+            onClick={() => setShowForm(true)}
+            className="inline-flex items-center gap-1 text-sm text-neutral-500 hover:text-neutral-700"
+          >
+            <Plus className="h-3.5 w-3.5" />
+            Hinzufugen
+          </button>
+        )}
+      </div>
+
+      {parties.length === 0 && !showForm && (
+        <p className="mt-4 py-4 text-center text-sm text-neutral-400">
+          Keine Parteien vorhanden.
+        </p>
+      )}
+
+      <div className="mt-3 space-y-2">
+        {parties.map((party) => (
+          <div
+            key={party.id}
+            className="flex items-center justify-between rounded-md border border-neutral-200 bg-white px-4 py-2.5"
+          >
+            <div>
+              <p className="text-sm font-medium text-neutral-900">
+                {party.name}
+              </p>
+              <div className="mt-0.5 flex gap-3 text-xs text-neutral-500">
+                {party.role && <span>{party.role}</span>}
+                {party.representative && (
+                  <span>Vertreter: {party.representative}</span>
+                )}
+              </div>
+            </div>
+            <button
+              onClick={() => deleteMutation.mutate(party.id)}
+              className="rounded p-1 text-neutral-300 hover:bg-neutral-100 hover:text-red-500"
+              title="Partei entfernen"
+            >
+              <Trash2 className="h-3.5 w-3.5" />
+            </button>
+          </div>
+        ))}
+      </div>
+
+      {showForm && (
+        <div className="mt-3 rounded-md border border-neutral-200 bg-neutral-50 p-4">
+          <div className="flex items-center justify-between">
+            <span className="text-sm font-medium text-neutral-700">
+              Neue Partei
+            </span>
+            <button
+              onClick={() => setShowForm(false)}
+              className="text-neutral-400 hover:text-neutral-600"
+            >
+              <X className="h-4 w-4" />
+            </button>
+          </div>
+          <form
+            onSubmit={(e) => {
+              e.preventDefault();
+              addMutation.mutate(form);
+            }}
+            className="mt-3 space-y-3"
+          >
+            <input
+              type="text"
+              required
+              placeholder="Name der Partei"
+              value={form.name}
+              onChange={(e) => setForm({ ...form, name: e.target.value })}
+              className={inputClass}
+            />
+            <div className="grid grid-cols-2 gap-3">
+              <select
+                value={form.role}
+                onChange={(e) => setForm({ ...form, role: e.target.value })}
+                className={inputClass}
+              >
+                <option value="">-- Rolle --</option>
+                {ROLE_OPTIONS.map((r) => (
+                  <option key={r} value={r}>
+                    {r}
+                  </option>
+                ))}
+              </select>
+              <input
+                type="text"
+                placeholder="Vertreter / Anwalt"
+                value={form.representative}
+                onChange={(e) =>
+                  setForm({ ...form, representative: e.target.value })
+                }
+                className={inputClass}
+              />
+            </div>
+            <div className="flex justify-end">
+              <button
+                type="submit"
+                disabled={addMutation.isPending}
+                className="rounded-md bg-neutral-900 px-3 py-1.5 text-sm font-medium text-white hover:bg-neutral-800 disabled:opacity-50"
+              >
+                {addMutation.isPending ? "..." : "Hinzufugen"}
+              </button>
+            </div>
+          </form>
+        </div>
+      )}
+    </div>
+  );
+}

frontend/src/components/layout/Sidebar.tsx

@@ -13,7 +13,7 @@ import {
 
 const navigation = [
   { name: "Dashboard", href: "/", icon: LayoutDashboard },
-  { name: "Akten", href: "/akten", icon: FolderOpen },
+  { name: "Akten", href: "/cases", icon: FolderOpen },
   { name: "Fristen", href: "/fristen", icon: Clock },
   { name: "Termine", href: "/termine", icon: Calendar },
   { name: "AI Analyse", href: "/ai", icon: Brain },