feat: v2.5.5 — AI Router renamed AI Proxy, reload onto new builds, update no longer spins

AI Proxy (was AI Router):
- server/lib/ai-proxies.js, proxy-apply.js, routes/ai-proxies.js mounted at
  /api/ai-proxies and the old /api/ai-routers; `router` still accepted on the
  start routes; profiles move to <CLAUDE_HOME>/agenthub-proxies/
- dashboard_runs.router renamed in place to proxy: an older build on the same
  DB fails on that column, so dev and prod sharing one DB update together
- a proxy's baseUrl stored as its root (a typed /v1 made /v1/v1/messages);
  Test probes Claude /v1/messages and Codex /v1/responses
- Settings → AI Proxy (/settings/ai-router redirects), ProxyPicker

Updates:
- every tab reloads onto the new UI build when its WebSocket reconnects to a
  server of another version (lib/newBuildReload.ts, once per version)
- Update now stops waiting on a plugin chain that failed or pulled nothing
  (the old server never goes down), and reloads as soon as a new version answers

Also:
- a pane whose command exits at once says so (EPANEEXITED) instead of
  "Command failed: tmux set-option … mouse on"
- the pane drag preview draws where the pane actually lands

client/src/components/settings/PricingSettings.tsx

@@ -4,7 +4,7 @@
  * computed from — as shown on a tool's Settings tab (Overview for Claude Code
  * and Codex, the Antigravity tab itself): Claude
  * Code's shows `claude-…` rows, Codex's shows OpenAI rows (`gpt-…`, `o<n>…`,
- * `codex-…`), Antigravity's Gemini rows (`gemini-…`). It is ONE table (a router model can serve either tool), so a
+ * `codex-…`), Antigravity's Gemini rows (`gemini-…`). It is ONE table (a proxy model can serve either tool), so a
  * **Show all models** switch lists every row, and a row added outside the
  * filter turns it on rather than vanishing. Reset Defaults reseeds Claude's
  * rates, so only the Claude tab offers it; the server re-fetches any row the

client/src/components/settings/__tests__/AiToolsSettings.test.tsx

@@ -49,7 +49,7 @@ const tool = (id: string, label: string, over: Partial<AiTool> = {}): AiTool =>
   prompt: { mode: "argv" },
   resume: false,
   bypass: false,
-  routerCapable: false,
+  proxyCapable: false,
   install: null,
   update: null,
   modelFlag: false,