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

server/__tests__/tmux.test.js

@@ -28,6 +28,19 @@ describe("tmux wrapper", () => {
     assert.equal(tmux.hasSession("agenthub-lane-1"), false);
   });
 
+  it("newSession names a command that exited at once instead of tmux's set-option error", () => {
+    tmux.__setExecImpl((args) => {
+      if (args[0] === "new-session") return "";
+      throw Object.assign(new Error("Command failed: tmux " + args.join(" ")), { status: 1 });
+    });
+    assert.throws(
+      () =>
+        tmux.newSession({ name: "agenthub-lane-4", cwd: "/tmp/repo", argv: ["claude", "-p", "x"] }),
+      (err) =>
+        err.code === "EPANEEXITED" && /exited as soon as it started: claude$/.test(err.message)
+    );
+  });
+
   it("newSession builds the correct argv", () => {
     const calls = [];
     tmux.__setExecImpl((args) => {