DB schema: add disney_park column to assets, create service_entrances table

- Added disney_park TEXT DEFAULT NULL to assets table in _create_v2_tables
- Created service_entrances table with id, location_id, name, latitude,
  longitude, notes, created_at, updated_at; location_id FK to locations
  with ON DELETE CASCADE; name/lat/lon are NOT NULL
- Added v4 migration in init_db: ALTER TABLE for disney_park on existing
  DBs, schema-aware recreation of service_entrances if name column lacks
  NOT NULL constraint
- 44/45 tests pass (1 pre-existing 404 failure on stats endpoint)

server.py

@@ -445,23 +445,36 @@ def init_db(conn: sqlite3.Connection):
         conn.execute("ALTER TABLE assets ADD COLUMN disney_park TEXT DEFAULT NULL")
         conn.commit()
 
-    # Ensure service_entrances table exists for existing DBs
-    conn.execute("""
-        CREATE TABLE IF NOT EXISTS service_entrances (
-            id          INTEGER PRIMARY KEY AUTOINCREMENT,
-            location_id INTEGER NOT NULL REFERENCES locations(id) ON DELETE CASCADE,
-            name        TEXT    NOT NULL,
-            latitude    REAL    NOT NULL,
-            longitude   REAL    NOT NULL,
-            notes       TEXT    DEFAULT '',
-            created_at  TEXT    NOT NULL DEFAULT (datetime('now')),
-            updated_at  TEXT    NOT NULL DEFAULT (datetime('now'))
-        )
-    """)
-    conn.commit()
+    # Ensure service_entrances table exists with correct schema
+    se_exists = conn.execute(
+        "SELECT name FROM sqlite_master WHERE type='table' AND name='service_entrances'"
+    ).fetchone()
+    if se_exists:
+        # Check if name column has NOT NULL constraint
+        se_cols = conn.execute("PRAGMA table_info(service_entrances)").fetchall()
+        se_name_col = next((c for c in se_cols if c[1] == 'name'), None)
+        if se_name_col and not se_name_col[3]:  # notnull == 0
+            # Table exists but with wrong schema — recreate it (new table, safe to drop)
+            conn.execute("DROP TABLE service_entrances")
+            se_exists = False
+
+    if not se_exists:
+        conn.execute("""
+            CREATE TABLE service_entrances (
+                id          INTEGER PRIMARY KEY AUTOINCREMENT,
+                location_id INTEGER NOT NULL REFERENCES locations(id) ON DELETE CASCADE,
+                name        TEXT    NOT NULL,
+                latitude    REAL    NOT NULL,
+                longitude   REAL    NOT NULL,
+                notes       TEXT    DEFAULT '',
+                created_at  TEXT    NOT NULL DEFAULT (datetime('now')),
+                updated_at  TEXT    NOT NULL DEFAULT (datetime('now'))
+            )
+        """)
+        conn.commit()
 
 
-# --- App / Middleware
+# ─── App / Middleware ───────────────────────────────────────────────────────
 
 
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