feat: add deadline management frontend (Phase 1G)

- Fristen page with list view (sortable, filterable by status/case)
- Calendar view with month navigation and deadline dots
- Deadline calculator page (proceeding type + trigger date = timeline)
- Traffic light urgency: red (overdue), amber (this week), green (OK)
- Backend: GET /api/deadlines (all tenant deadlines), GET /api/proceeding-types
- API client: added patch() method
- Types: DeadlineRule, ProceedingType, CalculatedDeadline, RuleTreeNode

backend/internal/handlers/deadline_rules.go

@@ -39,6 +39,17 @@ func (h *DeadlineRuleHandlers) List(w http.ResponseWriter, r *http.Request) {
 	writeJSON(w, http.StatusOK, rules)
 }
 
+// ListProceedingTypes handles GET /api/proceeding-types
+func (h *DeadlineRuleHandlers) ListProceedingTypes(w http.ResponseWriter, r *http.Request) {
+	types, err := h.rules.ListProceedingTypes()
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to list proceeding types")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, types)
+}
+
 // GetRuleTree handles GET /api/deadline-rules/{type}
 // {type} is the proceeding type code (e.g., "INF", "REV")
 func (h *DeadlineRuleHandlers) GetRuleTree(w http.ResponseWriter, r *http.Request) {

backend/internal/handlers/deadlines.go

@@ -20,6 +20,23 @@ func NewDeadlineHandlers(ds *services.DeadlineService, db *sqlx.DB) *DeadlineHan
 	return &DeadlineHandlers{deadlines: ds, db: db}
 }
 
+// ListAll handles GET /api/deadlines
+func (h *DeadlineHandlers) ListAll(w http.ResponseWriter, r *http.Request) {
+	tenantID, err := resolveTenant(r, h.db)
+	if err != nil {
+		handleTenantError(w, err)
+		return
+	}
+
+	deadlines, err := h.deadlines.ListAll(tenantID)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to list deadlines")
+		return
+	}
+
+	writeJSON(w, http.StatusOK, deadlines)
+}
+
 // ListForCase handles GET /api/cases/{caseID}/deadlines
 func (h *DeadlineHandlers) ListForCase(w http.ResponseWriter, r *http.Request) {
 	tenantID, err := resolveTenant(r, h.db)

backend/internal/router/router.go

@@ -81,6 +81,7 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config) http.Handler
 	scoped.HandleFunc("DELETE /api/parties/{partyId}", partyH.Delete)
 
 	// Deadlines
+	scoped.HandleFunc("GET /api/deadlines", deadlineH.ListAll)
 	scoped.HandleFunc("GET /api/cases/{caseID}/deadlines", deadlineH.ListForCase)
 	scoped.HandleFunc("POST /api/cases/{caseID}/deadlines", deadlineH.Create)
 	scoped.HandleFunc("PUT /api/deadlines/{deadlineID}", deadlineH.Update)
@@ -90,6 +91,7 @@ func New(db *sqlx.DB, authMW *auth.Middleware, cfg *config.Config) http.Handler
 	// Deadline rules (reference data)
 	scoped.HandleFunc("GET /api/deadline-rules", ruleH.List)
 	scoped.HandleFunc("GET /api/deadline-rules/{type}", ruleH.GetRuleTree)
+	scoped.HandleFunc("GET /api/proceeding-types", ruleH.ListProceedingTypes)
 
 	// Deadline calculator
 	scoped.HandleFunc("POST /api/deadlines/calculate", calcH.Calculate)

backend/internal/services/deadline_service.go

@@ -21,6 +21,23 @@ func NewDeadlineService(db *sqlx.DB) *DeadlineService {
 	return &DeadlineService{db: db}
 }
 
+// ListAll returns all deadlines for a tenant, ordered by due_date
+func (s *DeadlineService) ListAll(tenantID uuid.UUID) ([]models.Deadline, error) {
+	query := `SELECT id, tenant_id, case_id, title, description, due_date, original_due_date,
+	                 warning_date, source, rule_id, status, completed_at,
+	                 caldav_uid, caldav_etag, notes, created_at, updated_at
+	          FROM deadlines
+	          WHERE tenant_id = $1
+	          ORDER BY due_date ASC`
+
+	var deadlines []models.Deadline
+	err := s.db.Select(&deadlines, query, tenantID)
+	if err != nil {
+		return nil, fmt.Errorf("listing all deadlines: %w", err)
+	}
+	return deadlines, nil
+}
+
 // ListForCase returns all deadlines for a case, scoped to tenant
 func (s *DeadlineService) ListForCase(tenantID, caseID uuid.UUID) ([]models.Deadline, error) {
 	query := `SELECT id, tenant_id, case_id, title, description, due_date, original_due_date,