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/lib/docforge/nav/index.md

@@ -1,7 +0,0 @@
-# Nav
-
-::: docforge.nav
-- [Mkdocs](mkdocs.md)
-- [Resolver](resolver.md)
-- [Spec](spec.md)
-- [Wiki](wiki.md)