feat: implement plugin architecture and application settings with Svelte UI

- Added plugin base and loader for backend extensibility
- Implemented application settings management with config persistence
- Created Svelte-based frontend with Dashboard and Settings pages
- Added API routes for plugins, tasks, and settings
- Updated documentation and specifications
- Improved project structure and developer tools

backend/requirements.txt

@@ -1,9 +1,11 @@
-fastapi
-uvicorn
-pydantic
-authlib
-python-multipart
-starlette
-jsonschema
-requests
-keyring
+fastapi
+uvicorn
+pydantic
+authlib
+python-multipart
+starlette
+jsonschema
+requests
+keyring
+httpx
+PyYAML