fix(migrations): harden BAT-025 PostgreSQL verification

app/db/migrations.py

@@ -16,6 +16,10 @@ def get_alembic_config(settings: Settings) -> Config:
     config = Config(str(project_root / "alembic.ini"))
     config.set_main_option("script_location", str(project_root / "migrations"))
     config.set_main_option("sqlalchemy.url", settings.active_database_url.replace("%", "%%"))
+    # migrations/env.py must use this explicit settings object instead of the
+    # process-global cached Settings.  This keeps programmatic callers (notably
+    # isolated integration tests and runtime bootstrap) on their requested DB.
+    config.attributes["portfoliohub_settings"] = settings
     return config
 
 
@@ -29,7 +33,13 @@ def bootstrap_or_upgrade_to_head(settings: Settings) -> str:
         return "head"
 
     if _has_legacy_portfolio_schema(settings):
-        command.stamp(get_alembic_config(settings), "head")
+        # Runtime ensure_schema() can create the BAT-025 columns before Alembic is
+        # introduced.  Stamp only the revision immediately before BAT-025, then run
+        # the real upgrade so 0028 backfills a nullable pre-created `source` and
+        # converges constraints/defaults without replaying the older DDL chain.
+        config = get_alembic_config(settings)
+        command.stamp(config, "20260628_0027")
+        command.upgrade(config, "head")
         return "head"
 
     upgrade_to_head(settings)