feat: Projekt-Verwaltung verbessern — Archivieren, Loeschen, Wiederherstellen

- Backend: Restore-Endpoint (POST /projects/{id}/restore) und
  Hard-Delete-Endpoint (DELETE /projects/{id}/permanent) hinzugefuegt
- Frontend: Dreistufiger Dialog (Archivieren / Endgueltig loeschen mit
  Bestaetigungsdialog) statt einfachem Loeschen
- Archivierte Projekte aufklappbar in der Projektliste mit
  Wiederherstellen-Button
- CustomerTypeSelector entfernt (redundant seit Multi-Projekt)
- Default tenantId von 'default' auf UUID geaendert (Backend-400-Fix)
- SQL-Cast :state::jsonb durch CAST(:state AS jsonb) ersetzt (SQLAlchemy-Fix)
- snake_case/camelCase-Mapping fuer Backend-Response (NaN-Datum-Fix)
- projectInfo wird beim Laden vom Backend geholt (Header zeigt Projektname)
- API-Client erzeugt sich on-demand (Race-Condition-Fix fuer Projektliste)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend-compliance/compliance/api/project_routes.py

@@ -179,7 +179,7 @@ async def create_project(
         db.execute(
             text("""
                 INSERT INTO sdk_states (tenant_id, project_id, state, version, created_at, updated_at)
-                VALUES (:tenant_id, :project_id, :state::jsonb, 1, NOW(), NOW())
+                VALUES (:tenant_id, :project_id, CAST(:state AS jsonb), 1, NOW(), NOW())
             """),
             {
                 "tenant_id": tenant_id,
@@ -298,3 +298,79 @@ async def archive_project(
         raise
     finally:
         db.close()
+
+
+@router.post("/{project_id}/restore")
+async def restore_project(
+    project_id: str,
+    tenant_id: str = Depends(get_tenant_id),
+):
+    """Restore an archived project back to active."""
+    db = SessionLocal()
+    try:
+        result = db.execute(
+            text("""
+                UPDATE compliance_projects
+                SET status = 'active', archived_at = NULL, updated_at = NOW()
+                WHERE id = :project_id AND tenant_id = :tenant_id AND status = 'archived'
+                RETURNING id, tenant_id, name, description, customer_type, status,
+                          project_version, completion_percentage, created_at, updated_at
+            """),
+            {"project_id": project_id, "tenant_id": tenant_id},
+        )
+        row = result.fetchone()
+        if not row:
+            raise HTTPException(status_code=404, detail="Project not found or not archived")
+        db.commit()
+        logger.info("Restored project %s for tenant %s", project_id, tenant_id)
+        return _row_to_response(row)
+    except HTTPException:
+        raise
+    except Exception:
+        db.rollback()
+        raise
+    finally:
+        db.close()
+
+
+@router.delete("/{project_id}/permanent")
+async def permanently_delete_project(
+    project_id: str,
+    tenant_id: str = Depends(get_tenant_id),
+):
+    """Permanently delete a project and all associated data."""
+    db = SessionLocal()
+    try:
+        # Verify project exists and belongs to tenant
+        check = db.execute(
+            text("""
+                SELECT id FROM compliance_projects
+                WHERE id = :project_id AND tenant_id = :tenant_id
+            """),
+            {"project_id": project_id, "tenant_id": tenant_id},
+        ).fetchone()
+        if not check:
+            raise HTTPException(status_code=404, detail="Project not found")
+
+        # Delete sdk_states (CASCADE should handle this, but be explicit)
+        db.execute(
+            text("DELETE FROM sdk_states WHERE project_id = :project_id AND tenant_id = :tenant_id"),
+            {"project_id": project_id, "tenant_id": tenant_id},
+        )
+
+        # Delete the project itself
+        db.execute(
+            text("DELETE FROM compliance_projects WHERE id = :project_id AND tenant_id = :tenant_id"),
+            {"project_id": project_id, "tenant_id": tenant_id},
+        )
+
+        db.commit()
+        logger.info("Permanently deleted project %s for tenant %s", project_id, tenant_id)
+        return {"success": True, "id": project_id, "status": "deleted"}
+    except HTTPException:
+        raise
+    except Exception:
+        db.rollback()
+        raise
+    finally:
+        db.close()