fix(packaging): make mcp an optional backend and install doc backends in dev

Defer the mcp import in MCPServer.__init__ so 'import docforge' no longer requires the optional mcp dependency (matching the lazy MkDocs import). Add doc-forge[mkdocs,mcp] to the dev extra so the standard quality gate installs the backends the test suite needs.

CHANGELOG.md

@@ -33,11 +33,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   header, blue grey/teal palette, Roboto font, and additional material feature
   flags. The lib and api templates are unchanged.
 - Docstrings and wiki brought to the GSDFC (Google-style) standard.
+- The `dev` extra now includes the `mkdocs` and `mcp` extras so the
+  quality-gate environment can install and run the full test suite.
 
 ### Fixed
 - Loader-generated signatures render cleanly and unresolvable aliases are
   dropped from generated models.
 - Stub fixes for typed API surfaces.
+- `import docforge` no longer requires the optional `mcp` dependency; the
+  MCP server imports `mcp` lazily, matching the MkDocs backend.
 
 [Unreleased]: https://git.aetoskia.com/aetos/doc-forge/compare/0.0.7...HEAD
 [0.0.7]: https://git.aetoskia.com/aetos/doc-forge/compare/0.0.6...0.0.7