feat: dynamic model list via browser-captured ListModels RPC

[CharoenwitKunna]

Problem

The model list is hardcoded in \configs/models.json\ (currently 30 models). When Google adds new models (e.g. \gemini-3.7-flash,
obotics-er-2-preview), users must manually edit this file and restart the server.

Additionally, the \generativelanguage.googleapis.com/v1beta/models\ endpoint returns \403 API_KEY_SERVICE_BLOCKED\ when called from the browser context, making direct model discovery unreliable.

Proposed Solution

Auto-fetch the model list at runtime from the same \ListModels\ RPC endpoint that the AI Studio app calls on page load, via \page.on('response')\ capture in \BrowserManager.

Key changes:

• \BrowserManager: hook \page.on('response')\ before \page.goto\ to capture the app's own \ListModels\ response + request headers (URL, API key)
• \BrowserManager.fetchLiveModels(): return captured models (with configurable TTL), falling back to a manual RPC call using the captured URL/headers
• \BrowserManager._parseListModelsResponse(): parse the [[ [...], ... ]]\ protobuf+JSON array into \models.json-compatible objects
• \ConfigLoader: add \DYNAMIC_MODELS\ (default \ rue) and \DYNAMIC_MODELS_TTL\ (default \3600000\ ms) env vars
• \ProxyServerSystem: make \GET /v1/models\ and \GET /v1beta/models\ async, call \etchLiveModels()\ with static config as fallback
• \ProxyServerSystem: add \POST /api/models/refresh?persist=true\ endpoint for manual refresh

Benefits

• No hardcoded domain/key — auto-discovered from the browser's own captured request
• Works even if Google rotates the \CoJqbf\ backend domain or API key
• Zero-config — enabled by default, models update automatically on next request after TTL expires
• Backward compatible — \DYNAMIC_MODELS=false\ reverts to static \configs/models.json\

Testing

With \DYNAMIC_MODELS=true\ and empty \configs/models.json\ ({"models":[]}):

• Server fetches 36 live models via captured \ListModels\ RPC
• \GET /v1beta/models\ returns all 36 models
• Without capture fallback, auto-detects base URL from page config (\CoJqbf) and API key from page scripts

Environment

• Node.js on Windows
• Playwright with Camoufox (Firefox)
• AI Studio Build App with Google account auth