Add heuristic to fix code output

* remove deprecated script
* Optimize codebase extract & fix proposal handler token counting logic
* add caching + lock
* sort by modified timestamp
* cache cleanup

* Add toggle for disabling Dyad Pro
* Entering key for Dyad pro enables dyad pro

* Do not make API key input (password) - hurts usability
* Support LLM gateway (and add GPT 4.1 mini model)
* Show Dyad Pro button
* Fix to use auto (not dyad) for detecting dyad pro
* Fix description of gpt 4.1-mini