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

docs/wiki/05_development/04_mcp_guide.md

@@ -0,0 +1,51 @@
+# MCP Guide
+
+Doc-forge can export a machine-readable **MCP bundle** from a project's
+GSDFC docstrings and serve that bundle over the Model Context Protocol (MCP).
+The bundle is self-contained: readers can derive the full API reference —
+signatures, docstrings, and structure — for the documented project.
+
+## Building the bundle
+
+```bash
+doc-forge build --mcp --module docforge
+```
+
+This writes structured JSON into `docs/mcp/`:
+
+- `index.json` — project metadata and module count
+- `nav.json` — module list with `docs://modules/{module}` resource URIs
+- `modules/{dotted.path}.json` — per-module serialized documentation
+
+## Serving the bundle
+
+```bash
+doc-forge serve --mcp --module docforge
+```
+
+The `MCPServer` (in `docforge/servers/mcp_server.py`) exposes:
+
+| Resource             | Description                       |
+|----------------------|-----------------------------------|
+| `docs://index`       | Project metadata                  |
+| `docs://nav`         | Navigation structure              |
+| `docs://modules/{module}` | Individual module documentation |
+
+The server also registers a single diagnostic tool, `ping`, and is read-only.
+Missing resources are returned as structured error dictionaries rather than
+exceptions. The default transport is `streamable-http`; `stdio` and `sse` are
+supported via `MCPServer.run`.
+
+## Bundle contents
+
+Each module resource contains:
+
+- `path` — dotted module path
+- `docstring` — the raw GSDFC module docstring
+- `objects` — a recursive mapping of public symbols with `name`, `kind`,
+  `path`, `signature`, and `docstring`, plus nested `members`
+
+Because the bundle is generated from docstrings, the quality of the bundle
+equals the quality of the project's GSDFC docstrings. For docforge itself,
+the GSDFC specification is carried in `modules/docforge.json` via the
+`docforge/__init__.py` package docstring, making the bundle self-documenting.