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/pages/SettingsHub.tsx

@@ -46,7 +46,7 @@ import { Settings } from "./Settings";
 import { CcConfig } from "./CcConfig";
 import { CodexConfig } from "./CodexConfig";
 import { AiToolConfig } from "./AiToolConfig";
-import { AiRouterConfig } from "./AiRouterConfig";
+import { AiProxyConfig } from "./AiProxyConfig";
 import { GitCredentialsConfig } from "./GitCredentialsConfig";
 import { AppearanceSettings } from "../components/settings/AppearanceSettings";
 import { SnapshotSettings } from "../components/settings/SnapshotSettings";
@@ -82,7 +82,7 @@ const LEGACY_TOOL: Record<string, string> = {
   dashboard: "appearance",
   "claude-code": "agents/claude-code",
   codex: "agents/codex",
-  "ai-router": "ai-router",
+  "ai-router": "ai-proxy",
   "git-credentials": "git-credentials",
 };
 
@@ -117,7 +117,12 @@ function toolNavIcon(id: string, label: string) {
   return Icon;
 }
 
-const MOVED: Record<string, string> = { general: "appearance", pet: "appearance#pet" };
+const MOVED: Record<string, string> = {
+  general: "appearance",
+  pet: "appearance#pet",
+  // The AI Router → AI Proxy rename.
+  "ai-router": "ai-proxy",
+};
 
 /** An unknown section: say so, then show Appearance. */
 function UnknownSection({ name }: { name: string }) {
@@ -290,11 +295,11 @@ export function SettingsHub() {
         render: () => <AiToolConfig key={x.id} toolId={x.id} />,
       })),
     {
-      id: "ai-router",
+      id: "ai-proxy",
       group: "routing",
       Icon: Router,
-      ...s("aiRouter"),
-      render: () => <AiRouterConfig />,
+      ...s("aiProxy"),
+      render: () => <AiProxyConfig />,
     },
     {
       id: "pricing",