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/nav/spec.py

@@ -4,8 +4,19 @@ Navigation specification model.
 This module defines the ``NavSpec`` class, which represents the navigation
 structure defined by the user in the doc-forge navigation specification
 (typically ``docforge.nav.yml``).
+
+---
+
+Notes:
+    - The spec file supports an optional ``icon`` mapping for MkDocs theme
+      customization.
+    - All file references in ``groups`` are relative to the documentation root.
+
+---
 """
 
+from __future__ import annotations
+
 from pathlib import Path
 
 import yaml
@@ -38,10 +49,13 @@ class NavSpec:
         Initialize a NavSpec instance.
 
         Args:
-            home: Relative path to the home document.
-            groups: Mapping of group names to lists of path patterns
+            home (str | None):
+                Relative path to the home document.
+            groups (dict[str, list[str]]):
+                Mapping of group names to lists of path patterns
                 (glob expressions).
-            icon: Optional mapping of theme icon entries applied to the
+            icon (dict[str, str] | None):
+                Optional mapping of theme icon entries applied to the
                 generated MkDocs configuration.
         """
         self.home = home
@@ -49,15 +63,17 @@ class NavSpec:
         self.icon = icon
 
     @classmethod
-    def load(cls, path: Path) -> "NavSpec":
+    def load(cls, path: Path) -> NavSpec:
         """
         Load a navigation specification from a YAML file.
 
         Args:
-            path: Filesystem path to the navigation specification file.
+            path (Path):
+                Filesystem path to the navigation specification file.
 
         Returns:
-            A ``NavSpec`` instance representing the parsed configuration.
+            NavSpec:
+                A ``NavSpec`` instance representing the parsed configuration.
 
         Raises:
             FileNotFoundError: If the specified file does not exist.
@@ -105,8 +121,9 @@ class NavSpec:
         Return all path patterns referenced by the specification.
 
         Returns:
-            A list containing the home document (if defined) and all
-            group pattern entries.
+            list[str]:
+                A list containing the home document (if defined) and all
+                group pattern entries.
         """
         patterns: list[str] = []
 
@@ -127,10 +144,12 @@ def load_nav_spec(path: Path) -> NavSpec:
     corresponding ``NavSpec`` instance.
 
     Args:
-        path: Path to the navigation specification file.
+        path (Path):
+            Path to the navigation specification file.
 
     Returns:
-        A ``NavSpec`` instance representing the parsed specification.
+        NavSpec:
+            A ``NavSpec`` instance representing the parsed specification.
 
     Raises:
         FileNotFoundError: If the specification file does not exist.