test: remove TomlConfigSource and config_source flag tests

TOML-related tests no longer needed after Phase C retirement.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/test_supervisor_hotreload.py

@@ -355,40 +355,3 @@ class TestRateLimitGuarantee:
             f"Multiple NOTIFYs should not cause extra polls."
         )
 
-
-class TestBootstrapConfigFlag:
-    """Tests for CENTRAL_CONFIG_SOURCE bootstrap flag."""
-
-    def test_default_is_toml(self) -> None:
-        """Default config_source is 'toml'."""
-        from central.bootstrap_config import Settings
-
-        # Create settings with minimal required fields
-        settings = Settings(
-            db_dsn="postgresql://test@localhost/test",
-            _env_file=None,
-        )
-        assert settings.config_source == "toml"
-
-    def test_accepts_db(self, monkeypatch: pytest.MonkeyPatch) -> None:
-        """config_source accepts 'db' value."""
-        from central.bootstrap_config import Settings, get_settings
-
-        get_settings.cache_clear()
-        monkeypatch.setenv("CENTRAL_CONFIG_SOURCE", "db")
-        monkeypatch.setenv("CENTRAL_DB_DSN", "postgresql://test@localhost/test")
-
-        settings = get_settings()
-        assert settings.config_source == "db"
-
-    def test_rejects_invalid(self, monkeypatch: pytest.MonkeyPatch) -> None:
-        """config_source rejects invalid values."""
-        from pydantic import ValidationError
-        from central.bootstrap_config import Settings, get_settings
-
-        get_settings.cache_clear()
-        monkeypatch.setenv("CENTRAL_CONFIG_SOURCE", "invalid")
-        monkeypatch.setenv("CENTRAL_DB_DSN", "postgresql://test@localhost/test")
-
-        with pytest.raises(ValidationError):
-            get_settings()