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/auth/tenant_resolver.go

@@ -12,12 +12,8 @@ import (
 // Defined as an interface to avoid circular dependency with services.
 type TenantLookup interface {
 	FirstTenantForUser(ctx context.Context, userID uuid.UUID) (*uuid.UUID, error)
-<<<<<<< HEAD
 	VerifyAccess(ctx context.Context, userID, tenantID uuid.UUID) (bool, error)
-||||||| 82878df
-=======
 	GetUserRole(ctx context.Context, userID, tenantID uuid.UUID) (string, error)
->>>>>>> mai/pike/p0-role-based
 }
 
 // TenantResolver is middleware that resolves the tenant from X-Tenant-ID header
@@ -39,6 +35,7 @@ func (tr *TenantResolver) Resolve(next http.Handler) http.Handler {
 		}
 
 		var tenantID uuid.UUID
+		ctx := r.Context()
 
 		if header := r.Header.Get("X-Tenant-ID"); header != "" {
 			parsed, err := uuid.Parse(header)
@@ -46,38 +43,23 @@ func (tr *TenantResolver) Resolve(next http.Handler) http.Handler {
 				http.Error(w, `{"error":"invalid X-Tenant-ID"}`, http.StatusBadRequest)
 				return
 			}
-<<<<<<< HEAD
 
-			// Verify user has access to this tenant
-			hasAccess, err := tr.lookup.VerifyAccess(r.Context(), userID, parsed)
+			// Verify user has access and get their role
+			role, err := tr.lookup.GetUserRole(r.Context(), userID, parsed)
 			if err != nil {
 				slog.Error("tenant access check failed", "error", err, "user_id", userID, "tenant_id", parsed)
 				http.Error(w, `{"error":"internal error"}`, http.StatusInternalServerError)
 				return
 			}
-			if !hasAccess {
+			if role == "" {
 				http.Error(w, `{"error":"no access to tenant"}`, http.StatusForbidden)
 				return
 			}
 
-||||||| 82878df
-=======
-			// Verify user has access and get their role
-			role, err := tr.lookup.GetUserRole(r.Context(), userID, parsed)
-			if err != nil {
-				http.Error(w, "error checking tenant access", http.StatusInternalServerError)
-				return
-			}
-			if role == "" {
-				http.Error(w, "no access to this tenant", http.StatusForbidden)
-				return
-			}
->>>>>>> mai/pike/p0-role-based
 			tenantID = parsed
-			// Override the role from middleware with the correct one for this tenant
-			r = r.WithContext(ContextWithUserRole(r.Context(), role))
+			ctx = ContextWithUserRole(ctx, role)
 		} else {
-			// Default to user's first tenant (role already set by middleware)
+			// Default to user's first tenant
 			first, err := tr.lookup.FirstTenantForUser(r.Context(), userID)
 			if err != nil {
 				slog.Error("failed to resolve default tenant", "error", err, "user_id", userID)
@@ -89,9 +71,18 @@ func (tr *TenantResolver) Resolve(next http.Handler) http.Handler {
 				return
 			}
 			tenantID = *first
+
+			// Get role for default tenant
+			role, err := tr.lookup.GetUserRole(r.Context(), userID, tenantID)
+			if err != nil {
+				slog.Error("failed to get user role", "error", err, "user_id", userID, "tenant_id", tenantID)
+				http.Error(w, `{"error":"internal error"}`, http.StatusInternalServerError)
+				return
+			}
+			ctx = ContextWithUserRole(ctx, role)
 		}
 
-		ctx := ContextWithTenantID(r.Context(), tenantID)
+		ctx = ContextWithTenantID(ctx, tenantID)
 		next.ServeHTTP(w, r.WithContext(ctx))
 	})
 }