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/run/RunSetup.tsx

@@ -10,7 +10,7 @@
  *     (`POST /api/run/drop-image`);
  *   - `CwdAutocomplete` — the folder field the Add-workspace modal uses;
  *   - `ModelPicker` — a tool's own model list (`GET /api/ai-tools/:id/models`)
- *     or a fixed one (an AI Router's models), plus Custom…;
+ *     or a fixed one (an AI Proxy's models), plus Custom…;
  *   - `ModelMenu` — the same list as ONE composer chip, Claude Desktop's
  *     "Sonnet 5.5 · Medium": the main models with their hints, the rest under
  *     More models, Custom…, and the Effort slider (Faster → Smarter, a reset
@@ -671,7 +671,7 @@ const MODEL_CUSTOM = "__custom__";
 /**
  * The models `tool` can start on, the inherit entry (`""`) first: the tool's
  * own list (Codex's models cache, Claude's aliases named after the newest
- * version, a catalog tool's vendor rows), or `fixed` (a router's models);
+ * version, a catalog tool's vendor rows), or `fixed` (a proxy's models);
  * Claude's static aliases only when the server cannot answer. `loaded` once
  * the list is final.
  */
@@ -707,7 +707,7 @@ export function ModelPicker({
   value: string;
   onChange: (s: string) => void;
   tool: LaneTool;
-  /** A fixed list instead of the tool's own — an AI Router's models. */
+  /** A fixed list instead of the tool's own — an AI Proxy's models. */
   choices?: ModelChoice[];
   variant?: "field" | "ghost";
 }) {
@@ -781,7 +781,7 @@ export function ModelMenu({
   value: string;
   onChange: (s: string) => void;
   tool: LaneTool;
-  /** A fixed list instead of the tool's own — an AI Router's models. */
+  /** A fixed list instead of the tool's own — an AI Proxy's models. */
   choices?: ModelChoice[];
   /** Omitted for a tool that takes no effort. */
   effort?: EffortLevel;