Add cached image quickstart

tests/unit/test_compose.py

@@ -118,6 +118,7 @@ def _plan(
     with_egress: bool = False,
     supervise: bool = False,
     canary: bool = False,
+    image_policy: str = "fresh",
 ) -> DockerBottlePlan:
     """Build a fully-resolved DockerBottlePlan. Toggles cover the
     matrix the renderer's conditional-service logic branches on."""
@@ -148,6 +149,7 @@ def _plan(
         agent_name="demo",
         copy_cwd=False,
         user_cwd="/tmp/x",
+        image_policy=image_policy,
     )
     return DockerBottlePlan(
         spec=spec,
@@ -300,6 +302,11 @@ class TestSidecarBundleShape(unittest.TestCase):
         self.assertEqual("bot-bottle-sidecars:latest", sc["image"])
         self.assertEqual("Dockerfile.sidecars", sc["build"]["dockerfile"])
 
+    def test_cached_policy_omits_bundle_build(self):
+        sc = self._render(image_policy="cached")["services"]["sidecars"]
+        self.assertEqual("bot-bottle-sidecars:latest", sc["image"])
+        self.assertNotIn("build", sc)
+
     def test_bundle_container_name_uses_sidecars_prefix(self):
         sc = self._render()["services"]["sidecars"]
         self.assertEqual(f"bot-bottle-sidecars-{SLUG}", sc["container_name"])