refactor: add typed mcp source connection seam

src/wf_sources_mcp/__init__.py

@@ -21,23 +21,31 @@ from .auth import (
 )
 
 if TYPE_CHECKING:
+    from .connections import (
+        McpSourceConnection,
+        mcp_source_connection_from_connection_config,
+        mcp_source_connection_from_registry_entry,
+    )
     from .source_registry import (
         FileSourceRegistryStore,
-        HttpSourceTransport,
         McpSourceRegistryEntry,
         SourceRegistryFile,
         SourceRegistryStore,
-        SourceTransport,
-        StdioSourceTransport,
         connection_config_to_registry_entry,
         registry_entry_to_connection_config,
         workflow_mcp_source_to_connection_config,
     )
+    from .transports import (
+        HttpSourceTransport,
+        SourceTransport,
+        StdioSourceTransport,
+    )
 
 __all__ = [
     "AuthRecord",
     "FileSourceRegistryStore",
     "HttpSourceTransport",
+    "McpSourceConnection",
     "McpSourceRegistryEntry",
     "SourceRegistryFile",
     "SourceRegistryStore",
@@ -50,6 +58,8 @@ __all__ = [
     "mcp_auth_env",
     "mcp_auth_from_neutral",
     "mcp_auth_headers",
+    "mcp_source_connection_from_connection_config",
+    "mcp_source_connection_from_registry_entry",
     "neutral_auth_from_mcp",
     "registry_entry_to_connection_config",
     "workflow_mcp_source_to_connection_config",
@@ -57,14 +67,19 @@ __all__ = [
 
 
 def __getattr__(name: str) -> object:
+    if name in {
+        "McpSourceConnection",
+        "mcp_source_connection_from_connection_config",
+        "mcp_source_connection_from_registry_entry",
+    }:
+        from . import connections
+
+        return getattr(connections, name)
     if name in {
         "FileSourceRegistryStore",
-        "HttpSourceTransport",
         "McpSourceRegistryEntry",
         "SourceRegistryFile",
         "SourceRegistryStore",
-        "SourceTransport",
-        "StdioSourceTransport",
         "connection_config_to_registry_entry",
         "registry_entry_to_connection_config",
         "workflow_mcp_source_to_connection_config",
@@ -72,4 +87,12 @@ def __getattr__(name: str) -> object:
         from . import source_registry
 
         return getattr(source_registry, name)
+    if name in {
+        "HttpSourceTransport",
+        "SourceTransport",
+        "StdioSourceTransport",
+    }:
+        from . import transports
+
+        return getattr(transports, name)
     raise AttributeError(f"module {__name__!r} has no attribute {name!r}")