fix: delegate all live model fetching to agent provider_model_ids() (#411)

* fix: delegate all live model fetching to agent's provider_model_ids()

Previously _handle_live_models() maintained its own per-provider logic:
- anthropic, google, gemini returned 'not_supported' (hardcoded exclusions)
- openai-codex had a custom branch (added in v0.50.30)
- openai/copilot had hardcoded base URLs
- other providers fell through to a generic /v1/models fetch

Now the handler delegates entirely to hermes_cli.models.provider_model_ids(),
which is the agent's authoritative resolver:
- anthropic:    live fetch via /v1/models with correct API-key or OAuth headers
- copilot:      live fetch from api.githubcopilot.com/models with Copilot headers
- openai-codex: Codex OAuth endpoint + ~/.codex/ cache fallback
- nous:         live fetch from Nous inference portal
- deepseek, kimi-coding: generic OpenAI-compat /v1/models
- opencode-zen/go: OpenCode live catalog
- openrouter:   curated static list (live returns 300+ which is overwhelming)
- google/gemini, zai, minimax: static list (non-standard or Anthropic-compat endpoints)
- any others:   graceful static fallback

Also removed the client-side skip guard in _fetchLiveModels() (ui.js) that
blocked live fetching for anthropic, google, and gemini.

The hardcoded model lists in _PROVIDER_MODELS remain as the fallback when
credentials are missing or network is unavailable — they are never shown
when live data is available.

* docs: v0.50.31 release — version badge and CHANGELOG

---------

Co-authored-by: Nathan Esquenazi <nesquena@gmail.com>

static/ui.js

@@ -105,7 +105,7 @@ const _liveModelCache={};
 async function _fetchLiveModels(provider, sel){
   if(!provider||!sel) return;
   // Don't fetch for providers where we know it's unsupported or unnecessary
-  if(['anthropic','google','gemini'].includes(provider)) return;
+  // All providers now supported via agent's provider_model_ids() — no exclusions needed
   if(_liveModelCache[provider]) return; // already fetched this session
   try{
     const url=new URL('/api/models/live',location.origin);