fixed remove issue, made items avaiable for available view

trade-hub/backend/app/db.py

@@ -51,12 +51,46 @@ def get_db():
         db.close()
 
 
+def _upgrade_schema(engine) -> None:
+    """Add columns that `create_all` cannot add to an existing table.
+
+    PostgreSQL only: the SQLite database used by the tests is created fresh
+    from the models on every run, so it already has every column.
+    """
+    if engine.dialect.name != "postgresql":
+        return
+    with engine.begin() as conn:
+        conn.execute(
+            text(
+                "ALTER TABLE inventory_entries ADD COLUMN IF NOT EXISTS "
+                "visibility VARCHAR(16) NOT NULL DEFAULT 'private'"
+            )
+        )
+        conn.execute(
+            text(
+                """
+                DO $$
+                BEGIN
+                    IF NOT EXISTS (
+                        SELECT 1 FROM pg_constraint
+                        WHERE conname = 'ck_inventory_visibility'
+                    ) THEN
+                        ALTER TABLE inventory_entries
+                            ADD CONSTRAINT ck_inventory_visibility
+                            CHECK (visibility IN ('private', 'available'));
+                    END IF;
+                END $$
+                """
+            )
+        )
+
+
 def init_db(wait_seconds: int = 0, interval: float = 1.0) -> None:
     """Create missing tables, retrying while PostgreSQL finishes booting.
 
     `create_all(checkfirst=True)` is idempotent and safe to run on every start.
-    It does not migrate changed columns; introduce Alembic when the schema
-    starts evolving in place.
+    Additive columns for existing deployments are applied afterwards; changing
+    or dropping an existing column still requires Alembic.
     """
     deadline = time.monotonic() + max(wait_seconds, 0)
     while True:
@@ -65,6 +99,7 @@ def init_db(wait_seconds: int = 0, interval: float = 1.0) -> None:
             with engine.connect() as conn:
                 conn.execute(text("SELECT 1"))
             Base.metadata.create_all(bind=engine, checkfirst=True)
+            _upgrade_schema(engine)
             return
         except (OperationalError, IntegrityError, ProgrammingError) as exc:
             # A concurrent startup may have created the tables first.