test(gateway-image): probe package imports, not pre-refactor flat modules

test_python_imports_supervise_module probed the image with
`import supervise; import supervise_server`, the flat sibling modules that
5ad3449 replaced. They now live in the installed package, so the test fails
with ModuleNotFoundError when actually run.

It went unnoticed because the whole class carries a GITEA_ACTIONS skip — it
is interactive-only, so CI never executes it.

All 4 tests in the class now pass against a freshly built gateway image.

Closes #429.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/integration/test_gateway_image.py

@@ -86,13 +86,12 @@ class TestGatewayImage(unittest.TestCase):
         self.assertIn("Mitmproxy", out)
 
     def test_python_imports_supervise_module(self):
-        # The bundle's supervise daemon imports `supervise` as a
+        # The supervise daemon is installed as part of the bot_bottle
-        # same-directory sibling of `supervise_server`. Probe the
+        # package (5ad3449), not as flat sibling modules under /app.
-        # import resolves with `python3 -c` from /app (the
+        # Probe that the package imports resolve inside the image.
-        # Dockerfile's WORKDIR).
         rc, out = self._run_in_image(
             "python3", "-c",
-            "import supervise; import supervise_server; print('ok')",
+            "from bot_bottle import supervise, supervise_server; print('ok')",
         )
         self.assertEqual(0, rc, msg=out)
         self.assertIn("ok", out)