refactor: move docs transformOptions to clanLib to reduce rebuilds

- Add clanLib.docs.stripStorePathsFromDeclarations to deduplicate code
- Update all documentation generation to use the shared function
- This strips store paths from option declarations to prevent options.json
  from rebuilding when only store paths change but content remains the same
- Reduces unnecessary documentation rebuilds when making unrelated changes

lib/default.nix

@@ -45,6 +45,7 @@ lib.fix (
     introspection = import ./introspection { inherit lib; };
     jsonschema = import ./jsonschema { inherit lib; };
     facts = import ./facts.nix { inherit lib; };
+    docs = import ./docs.nix { inherit lib; };
 
     # flakes
     flakes = clanLib.callLib ./flakes.nix { };