test: remove 169 change-detector tests across 21 files (#11472)

First pass of test-suite reduction to address flaky CI and bloat.

Removed tests that fall into these change-detector patterns:

1. Source-grep tests (tests/gateway/test_feishu.py, test_email.py): tests
   that call inspect.getsource() on production modules and grep for string
   literals. Break on any refactor/rename even when behavior is correct.

2. Platform enum tautologies (every gateway/test_X.py): assertions like
   `Platform.X.value == 'x'` duplicated across ~9 adapter test files.

3. Toolset/PLATFORM_HINTS/setup-wizard registry-presence checks: tests that
   only verify a key exists in a dict. Data-layout tests, not behavior.

4. Argparse wiring tests (test_argparse_flag_propagation, test_subparser_routing
   _fallback): tests that do parser.parse_args([...]) then assert args.field.
   Tests Python's argparse, not our code.

5. Pure dispatch tests (test_plugins_cmd.TestPluginsCommandDispatch): patch
   cmd_X, call plugins_command with matching action, assert mock called.
   Tests the if/elif chain, not behavior.

6. Kwarg-to-mock verification (test_auxiliary_client ~45 tests,
   test_web_tools_config, test_gemini_cloudcode, test_retaindb_plugin): tests
   that mock the external API client, call our function, and assert exact
   kwargs. Break on refactor even when behavior is preserved.

7. Schedule-internal "function-was-called" tests (acp/test_server scheduling
   tests): tests that patch own helper method, then assert it was called.

Kept behavioral tests throughout: error paths (pytest.raises), security
tests (path traversal, SSRF, redaction), message alternation invariants,
provider API format conversion, streaming logic, memory contract, real
config load/merge tests.

Net reduction: 169 tests removed. 38 empty classes cleaned up.

Collected before: 12,522 tests
Collected after:  12,353 tests

tests/gateway/test_bluebubbles.py

@@ -20,11 +20,6 @@ def _make_adapter(monkeypatch, **extra):
     return BlueBubblesAdapter(cfg)
 
 
-class TestBlueBubblesPlatformEnum:
-    def test_bluebubbles_enum_exists(self):
-        assert Platform.BLUEBUBBLES.value == "bluebubbles"
-
-
 class TestBlueBubblesConfigLoading:
     def test_apply_env_overrides_bluebubbles(self, monkeypatch):
         monkeypatch.setenv("BLUEBUBBLES_SERVER_URL", "http://localhost:1234")
@@ -41,15 +36,6 @@ class TestBlueBubblesConfigLoading:
         assert bc.extra["password"] == "secret"
         assert bc.extra["webhook_port"] == 9999
 
-    def test_connected_platforms_includes_bluebubbles(self, monkeypatch):
-        monkeypatch.setenv("BLUEBUBBLES_SERVER_URL", "http://localhost:1234")
-        monkeypatch.setenv("BLUEBUBBLES_PASSWORD", "secret")
-        from gateway.config import GatewayConfig, _apply_env_overrides
-
-        config = GatewayConfig()
-        _apply_env_overrides(config)
-        assert Platform.BLUEBUBBLES in config.get_connected_platforms()
-
     def test_home_channel_set_from_env(self, monkeypatch):
         monkeypatch.setenv("BLUEBUBBLES_SERVER_URL", "http://localhost:1234")
         monkeypatch.setenv("BLUEBUBBLES_PASSWORD", "secret")
@@ -273,29 +259,6 @@ class TestBlueBubblesGuidResolution:
         assert result is None
 
 
-class TestBlueBubblesToolsetIntegration:
-    def test_toolset_exists(self):
-        from toolsets import TOOLSETS
-
-        assert "hermes-bluebubbles" in TOOLSETS
-
-    def test_toolset_in_gateway_composite(self):
-        from toolsets import TOOLSETS
-
-        gateway = TOOLSETS["hermes-gateway"]
-        assert "hermes-bluebubbles" in gateway["includes"]
-
-
-class TestBlueBubblesPromptHint:
-    def test_platform_hint_exists(self):
-        from agent.prompt_builder import PLATFORM_HINTS
-
-        assert "bluebubbles" in PLATFORM_HINTS
-        hint = PLATFORM_HINTS["bluebubbles"]
-        assert "iMessage" in hint
-        assert "plain text" in hint
-
-
 class TestBlueBubblesAttachmentDownload:
     """Verify _download_attachment routes to the correct cache helper."""