Add package structure and resource path utilities

- Created langbot/ package with __init__.py and __main__.py entry point
- Added paths utility to find frontend and resource files from package installation
- Updated config loading to use resource paths
- Updated frontend serving to use resource paths
- Added MANIFEST.in for package data inclusion
- Updated pyproject.toml with build system and entry points

Co-authored-by: RockChinQ <45992437+RockChinQ@users.noreply.github.com>

pkg/api/http/controller/main.py

@@ -86,7 +86,9 @@ class HTTPController:
             ginst = g(self.ap, self.quart_app)
             await ginst.initialize()
 
-        frontend_path = 'web/out'
+        from ....utils import paths
+        
+        frontend_path = paths.get_frontend_path()
 
         @self.quart_app.route('/')
         async def index():