docs: bring docforge docstrings and wiki to GSDFC standard

- fix GSDFC spec contradictions in __init__ docstring (parenthesized types, fenced-block rule) and sync generated README
- rewrite docstrings across loaders, models, nav, servers, renderers, cli; sync .pyi stubs
- add pydoclint (google style) gate to dev extras and pyproject config
- fix mcp nav resources doc:// -> docs://
- refresh docs/lib and docs/mcp, drop stale docforge/ duplicate group
- update wiki pages and add GSDFC + MCP guides under 05_development

docforge/loaders/griffe_loader.pyi

@@ -11,6 +11,7 @@ class GriffeLoader:
     """Griffe-based introspection loaders.
 
     This is the only supported introspection backend in doc-forge.
+    Converts Griffe results into `Project`, `Module`, and `DocObject` models.
     """
 
     def __init__(self) -> None: ...
@@ -18,7 +19,7 @@ class GriffeLoader:
         self,
         module_paths: list[str],
         project_name: str | None = ...,
-        skip_import_errors: bool = ...,
+        skip_import_errors: bool | None = ...,
     ) -> Project:
         """Load a documentation project from Python modules."""