docs: full refresh per DOCSPLAN (auth subsystem, backends model, access classes, sudo table, state-model mechanics) + 3 stale docstrings

lib/network.py

@@ -191,7 +191,7 @@ def render_network_file(iface_name: str, cfg_entry: dict[str, Any]) -> str:
             todo.md (addresses, gateway, dns, routes, link, dhcp_client, etc.).
 
     Returns:
-        INI content string ready to write as 50-<name>.network file.
+        INI content string ready to write as 99-<name>.network file.
     """
     lines: list[str] = []
     d = cfg_entry

lib/schema.py

@@ -227,7 +227,7 @@ class NginxState(TypedDict):
     Attributes:
         config: config/nginx/config.json.
         domains: Flattened domain entries (one per domain+path).
-        status: ``{"pending_changes": bool}``.
+        status: ``{"pending_changes": bool, "pending_diff": list[dict]}``.
         timestamp: ISO-8601 collection time.
     """