fix(ollama): bypass proxy for loopback endpoints and add auto-start/install workflow

[BerryUIKI]

Summary

1. Fix Loopback 502 Bad Gateway: Automatically configure \NO_PROXY\ on startup and enforce \ rust_env=False\ across local engine HTTP clients (\ollama_supervisor, \comfy_runner, \engine_manager, \webui_runner), preventing local loopback connections from being intercepted by system proxies (e.g. Clash on 127.0.0.1:7890).
2. Auto-Start & Readiness Polling: \ollama_supervisor.pull_model_stream\ now automatically launches the Ollama background daemon if it is stopped, polling until ready before initiating model pull.
3. Install Support & User Guidance: Added /api/v1/ollama/install\ endpoint with winget/website fallback.
4. SetupWizardModal UX Enhancements: Differentiate between not-installed, stopped, and running states; provide 1-click install and direct website links; show pre-checks and human-friendly error messages on model pull.