feat: document templates with auto-fill from case data (P1)

- Database: kanzlai.document_templates table with RLS policies
- Seed: 4 system templates (Klageerwiderung UPC, Berufungsschrift,
  Mandatsbestätigung, Kostenrechnung)
- Backend: TemplateService (CRUD + render), TemplateHandler with
  endpoints: GET/POST /api/templates, GET/PUT/DELETE /api/templates/{id},
  POST /api/templates/{id}/render?case_id=X
- Template variables: case.*, party.*, tenant.*, user.*, date.*, deadline.*
- Frontend: /vorlagen page with category filters, template detail/editor,
  render flow (select case -> preview -> copy/download), variable toolbar
- Quick action: "Schriftsatz erstellen" button on case detail page
- Also: resolved merge conflicts between audit-trail and role-based branches,
  added missing Notification/AuditLog types to frontend

backend/internal/router/router.go

@@ -29,14 +29,9 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config, calDAVSvc *se
 	deadlineRuleSvc := services.NewDeadlineRuleService(db)
 	calculator := services.NewDeadlineCalculator(holidaySvc)
 	storageCli := services.NewStorageClient(cfg.SupabaseURL, cfg.SupabaseServiceKey)
-<<<<<<< HEAD
 	documentSvc := services.NewDocumentService(db, storageCli, auditSvc)
-||||||| 82878df
-	documentSvc := services.NewDocumentService(db, storageCli)
-=======
-	documentSvc := services.NewDocumentService(db, storageCli)
 	assignmentSvc := services.NewCaseAssignmentService(db)
->>>>>>> mai/pike/p0-role-based
+	templateSvc := services.NewTemplateService(db, auditSvc)
 
 	// AI service (optional — only if API key is configured)
 	var aiH *handlers.AIHandler
@@ -71,6 +66,7 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config, calDAVSvc *se
 	eventH := handlers.NewCaseEventHandler(db)
 	docH := handlers.NewDocumentHandler(documentSvc)
 	assignmentH := handlers.NewCaseAssignmentHandler(assignmentSvc)
+	templateH := handlers.NewTemplateHandler(templateSvc, caseSvc, partySvc, deadlineSvc, tenantSvc)
 
 	// Public routes
 	mux.HandleFunc("GET /health", handleHealth(db))
@@ -112,7 +108,7 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config, calDAVSvc *se
 	scoped.HandleFunc("GET /api/cases", caseH.List)
 	scoped.HandleFunc("POST /api/cases", perm(auth.PermCreateCase, caseH.Create))
 	scoped.HandleFunc("GET /api/cases/{id}", caseH.Get)
-	scoped.HandleFunc("PUT /api/cases/{id}", caseH.Update)    // case-level access checked in handler
+	scoped.HandleFunc("PUT /api/cases/{id}", caseH.Update)
 	scoped.HandleFunc("DELETE /api/cases/{id}", perm(auth.PermCreateCase, caseH.Delete))
 
 	// Parties — same access as case editing
@@ -138,7 +134,7 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config, calDAVSvc *se
 	// Deadline calculator — all can use
 	scoped.HandleFunc("POST /api/deadlines/calculate", calcH.Calculate)
 
-	// Appointments — all can manage (PermManageAppointments granted to all)
+	// Appointments — all can manage
 	scoped.HandleFunc("GET /api/appointments/{id}", apptH.Get)
 	scoped.HandleFunc("GET /api/appointments", apptH.List)
 	scoped.HandleFunc("POST /api/appointments", perm(auth.PermManageAppointments, apptH.Create))
@@ -162,21 +158,23 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config, calDAVSvc *se
 	// Dashboard — all can view
 	scoped.HandleFunc("GET /api/dashboard", dashboardH.Get)
 
-<<<<<<< HEAD
 	// Audit log
 	scoped.HandleFunc("GET /api/audit-log", auditH.List)
 
-	// Documents
-||||||| 82878df
-	// Documents
-=======
-	// Documents — all can upload, delete checked in handler (own vs all)
->>>>>>> mai/pike/p0-role-based
+	// Documents — all can upload, delete checked in handler
 	scoped.HandleFunc("GET /api/cases/{id}/documents", docH.ListByCase)
 	scoped.HandleFunc("POST /api/cases/{id}/documents", perm(auth.PermUploadDocuments, docH.Upload))
 	scoped.HandleFunc("GET /api/documents/{docId}", docH.Download)
 	scoped.HandleFunc("GET /api/documents/{docId}/meta", docH.GetMeta)
-	scoped.HandleFunc("DELETE /api/documents/{docId}", docH.Delete) // permission check inside handler
+	scoped.HandleFunc("DELETE /api/documents/{docId}", docH.Delete)
+
+	// Document templates — all can view, create/edit needs PermCreateCase
+	scoped.HandleFunc("GET /api/templates", templateH.List)
+	scoped.HandleFunc("GET /api/templates/{id}", templateH.Get)
+	scoped.HandleFunc("POST /api/templates", perm(auth.PermCreateCase, templateH.Create))
+	scoped.HandleFunc("PUT /api/templates/{id}", perm(auth.PermCreateCase, templateH.Update))
+	scoped.HandleFunc("DELETE /api/templates/{id}", perm(auth.PermCreateCase, templateH.Delete))
+	scoped.HandleFunc("POST /api/templates/{id}/render", templateH.Render)
 
 	// AI endpoints (rate limited: 5 req/min burst 10 per IP)
 	if aiH != nil {
@@ -185,7 +183,6 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config, calDAVSvc *se
 		scoped.HandleFunc("POST /api/ai/summarize-case", perm(auth.PermAIExtraction, aiLimiter.LimitFunc(aiH.SummarizeCase)))
 	}
 
-<<<<<<< HEAD
 	// Notifications
 	if notifH != nil {
 		scoped.HandleFunc("GET /api/notifications", notifH.List)
@@ -197,11 +194,6 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config, calDAVSvc *se
 	}
 
 	// CalDAV sync endpoints
-||||||| 82878df
-	// CalDAV sync endpoints
-=======
-	// CalDAV sync endpoints — settings permission required
->>>>>>> mai/pike/p0-role-based
 	if calDAVSvc != nil {
 		calDAVH := handlers.NewCalDAVHandler(calDAVSvc)
 		scoped.HandleFunc("POST /api/caldav/sync", perm(auth.PermManageSettings, calDAVH.TriggerSync))