no-mistakes(review): Add startup self-heal guard for show_in_form column

tests/test_categories_and_units.py

@@ -138,6 +138,41 @@ async def test_seed_syncs_show_in_form_on_existing_rows(client):
         assert len(created) >= 1
 
 
+async def test_legacy_db_self_heals_show_in_form_column():
+    """A pre-Sprint-A categories table (no show_in_form) gets the column on startup."""
+    from sqlalchemy import text
+
+    from app.core.database import engine
+    from app.main import ensure_legacy_schema
+
+    async with engine.begin() as conn:
+        await conn.execute(text("DROP TABLE IF EXISTS tickets"))
+        await conn.execute(text("DROP TABLE IF EXISTS categories"))
+        await conn.execute(
+            text(
+                "CREATE TABLE categories ("
+                "id INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT, "
+                "type VARCHAR(20) NOT NULL, "
+                "name VARCHAR(100) NOT NULL, "
+                "parent_id INTEGER, "
+                "sla_urgency VARCHAR(10))"
+            )
+        )
+        await ensure_legacy_schema(conn)
+        result = await conn.execute(text("PRAGMA table_info(categories)"))
+        assert "show_in_form" in {row[1] for row in result}
+
+    # Idempotent on the next startup
+    async with engine.begin() as conn:
+        await ensure_legacy_schema(conn)
+        result = await conn.execute(text("PRAGMA table_info(categories)"))
+        assert "show_in_form" in {row[1] for row in result}
+
+    async with engine.begin() as conn:
+        await conn.execute(text("DROP TABLE IF EXISTS categories"))
+        await conn.execute(text("DROP TABLE IF EXISTS tickets"))
+
+
 # ── Unit hierarchy ────────────────────────────────────────────────────
 async def test_units_building_filter(client):
     """GET /api/tickets/units?building= filters to one building."""