diff --git a/AGENTS.md b/AGENTS.md
index 1b1abc4..96fa43d 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -39,7 +39,7 @@ Users, units, and categories are auto-seeded on first startup via lifespan hook:
 - 120 apartment units (East/West, 10 floors × 6 apts per wing)
 - Default password for all seed users: `denya123`
 - Units load from `apartment_mapping.json` if present, else built-in fallback
-- Categories: 20 top-level (10 Maintenance, 6 CS, 4 Emergency) with sub-categories, seeded from `app/services/seed.py::SEED_CATEGORIES_DATA`
+- Categories: 23 top-level (13 Maintenance, 6 CS, 4 Emergency) with sub-categories, seeded from `app/services/seed.py::SEED_CATEGORIES_DATA`
 
 ## Key API endpoints
 
@@ -72,15 +72,15 @@ Frontend: Alpine.js (CDN) + Tailwind CSS (CDN). Auth state in localStorage. Role
 | Method | Path | Auth | Description |
 |--------|------|------|-------------|
 | POST | `/api/tickets` | Bearer | Create ticket (auto-number PAV-YYYY-NNNNN) |
-| GET | `/api/tickets` | No | List tickets (filter: status, priority, property, category_id, assigned_to, date_from, date_to) |
+| GET | `/api/tickets` | No | List tickets (filter: status, priority, property, building, unit_id, category_id, assigned_to, date_from, date_to) |
 | GET | `/api/tickets/{id}` | No | Get ticket detail with timeline, photos, SLA status |
 | PATCH | `/api/tickets/{id}` | Bearer | Update ticket (validates status transitions) |
 | POST | `/api/tickets/{id}/status` | Bearer | Change status with note |
 | GET | `/api/tickets/{id}/sla` | No | Check SLA breach status |
 | POST | `/api/tickets/{id}/photos` | Bearer | Upload photos (multipart, is_before param) |
 | GET | `/api/tickets/{id}/photos` | No | List photos |
-| GET | `/api/tickets/categories` | No | Category tree (optional `?type=` filter) |
-| GET | `/api/tickets/categories/flat` | No | Flat category list |
+| GET | `/api/tickets/categories` | No | Category tree (filters: `type`; alert-only hidden unless `include_hidden=true`) |
+| GET | `/api/tickets/categories/flat` | No | Flat category list (same `type`/`include_hidden` filters) |
 
 ## Auth
 
@@ -123,7 +123,9 @@ Tables: users, units, categories, tickets, ticket_timeline, ticket_photos, escal
   (`/api/tickets/categories[/flat]`) exclude them unless `include_hidden=true` (used by the
   emergency quick path on `tickets/new.html`). Seed taxonomy lives in `app/services/seed.py`
   (`SEED_CATEGORIES_DATA`); the Lost Property → Missing Item rename is a data migration
-  (alembic `b2f4a6c8e0d2`). Seeds are idempotent and sync `show_in_form` on existing rows.
+  (alembic `b2f4a6c8e0d2`), with a startup self-heal (`app/main.py::ensure_legacy_schema`)
+  applying the same column/rename fix to legacy create_all databases. Seeds are idempotent
+  and sync `show_in_form` on existing rows.
 - Location hierarchy is Property → Building → Apartment (uses `Unit.building`).
   `GET /api/tickets/units/grouped` returns `{property: {building: [units]}}`;
   `/api/tickets` accepts additive `building`/`unit_id` filters. Unit data is deterministic
diff --git a/app/routers/tickets.py b/app/routers/tickets.py
index d7748b6..ac23cce 100644
--- a/app/routers/tickets.py
+++ b/app/routers/tickets.py
@@ -2,7 +2,6 @@
 
 from __future__ import annotations
 
-import os
 import uuid
 from datetime import datetime
 from pathlib import Path
diff --git a/app/schemas/ticket.py b/app/schemas/ticket.py
index 303f1f7..044612e 100644
--- a/app/schemas/ticket.py
+++ b/app/schemas/ticket.py
@@ -5,7 +5,7 @@ from __future__ import annotations
 from datetime import datetime
 from decimal import Decimal
 
-from pydantic import BaseModel, Field
+from pydantic import BaseModel
 
 
 # ── Unit ─────────────────────────────────────────────────────────────
diff --git a/tests/conftest.py b/tests/conftest.py
index c233947..23c8bd1 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -9,18 +9,17 @@ from __future__ import annotations
 
 import os
 import tempfile
-from pathlib import Path
 
 _TMP_DIR = tempfile.mkdtemp(prefix="denya-test-")
 os.environ["DATABASE_URL"] = f"sqlite+aiosqlite:///{_TMP_DIR}/test.db"
 
-import pytest_asyncio
-from httpx import ASGITransport, AsyncClient
+import pytest_asyncio  # noqa: E402  (DATABASE_URL must be set before app imports)
+from httpx import ASGITransport, AsyncClient  # noqa: E402
 
-from app.core.database import Base, async_session_factory, engine
-from app.main import app
-from app.models.ticket import Ticket
-from app.services.seed import seed_categories, seed_units, seed_users
+from app.core.database import Base, async_session_factory, engine  # noqa: E402
+from app.main import app  # noqa: E402
+from app.models.ticket import Ticket  # noqa: E402
+from app.services.seed import seed_categories, seed_units, seed_users  # noqa: E402
 
 
 @pytest_asyncio.fixture