test: reorganize suite into unit/integration/canaries directories

Replace the hand-maintained INTEGRATION_NAMES classifier (and the
bespoke run_tests.py around it) with a directory-driven split:

  tests/unit/         unit tests, always run
  tests/integration/  Docker-dependent, skip cleanly without Docker
  tests/canaries/     upstream-regression checks, opt-in via
                      CLAUDE_BOTTLE_RUN_CANARIES=1

The pinned-pipelock-image check moves to the canary suite — it tests
upstream packaging, not our code, so it shouldn't gate every dev push.
A scheduled canaries.yml workflow runs it weekly.

The manifest-runtime tests collapse the four assertRaises cases for
distinct 'runtime' values into one subTest loop and drop the
error-message-wording assertions; the contract is "any value is
rejected", not "the error literally contains 'auto-detect'".

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/unit/test_manifest_runtime.py

@@ -0,0 +1,39 @@
+"""Unit: bottle 'runtime' field is no longer supported (PRD 0003).
+
+gVisor is now auto-detected by the Docker factory. A manifest carrying
+the legacy 'runtime' field must fail, regardless of value, rather than
+silently ignoring."""
+
+import unittest
+
+from claude_bottle.log import Die
+from claude_bottle.manifest import Bottle, Manifest
+
+
+def _manifest_with_runtime(value: object) -> dict:
+    return {
+        "bottles": {"dev": {"runtime": value}},
+        "agents": {"demo": {"skills": [], "prompt": "", "bottle": "dev"}},
+    }
+
+
+class TestManifestRuntimeRemoved(unittest.TestCase):
+    def test_loads_when_runtime_absent(self):
+        m = Manifest.from_json_obj({
+            "bottles": {"dev": {}},
+            "agents": {"demo": {"skills": [], "prompt": "", "bottle": "dev"}},
+        })
+        self.assertIn("dev", m.bottles)
+
+    def test_bottle_dataclass_has_no_runtime_attribute(self):
+        self.assertFalse(hasattr(Bottle(), "runtime"))
+
+    def test_any_runtime_value_is_rejected(self):
+        for value in ("runsc", "runc", "kata-runtime", "", 42, None):
+            with self.subTest(value=value):
+                with self.assertRaises(Die):
+                    Manifest.from_json_obj(_manifest_with_runtime(value))
+
+
+if __name__ == "__main__":
+    unittest.main()