perf: rest animations, cheaper chat typing and server polls, async per-tool hooks

UI
- No animation runs forever: Sagi moods, the custom pet sprite, status dots
  (pulse-dot, pulse-slow, ping) and the chat shimmer play a few cycles and
  rest. An infinite animation kept the browser drawing 60 frames a second.
- useSagiBrain: frames that only move lastActivityAt by <1 s keep the old
  state; the 1 s tick re-renders only when the mood changes.
- ConversationView and MessageList are memoized and PaneChat passes stable
  callbacks: typing in the chat box no longer re-renders the conversation.
- The chat's 700 ms menu poll reads plain text first and scans the terminal
  cell by cell (reusing one cell) only when a row could be a menu cursor row.

Server
- GET /sessions/:id/transcript?after=N skips lines <= N before JSON.parse.
- GET /sessions/:id/outline is cached until the session's events change.
- broadcastLane uses the cached tmux.liveSessions(); tmux.hasSession answers
  "yes" from the fresh shared list instead of a synchronous spawn (50-150 ms
  per psmux call on Windows, blocking terminal echo).
- pane-mode polls every 150 ms; writeHourly writes only changed hour buckets.
- /api/metrics: agenthub_event_loop_delay_seconds{quantile}.

Hooks
- PreToolUse/PostToolUse run with "async": true (settings installer,
  plugin.json, S3 managed settings): Claude Code no longer waits a Node start
  before and after every tool call.

Committed with --no-verify at the owner's request: the pre-commit full server
suite fails on 9 tests that fail identically on 0c2f498 (lane-sync merge: no
git identity on this host; read-pool; resolveHost; codex-usage 1 ms flake).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

client/src/lib/__tests__/panePaste.test.ts

@@ -24,6 +24,7 @@ import {
   readRunMenu,
   registerPane,
   takeRunInput,
+  MENU_CURSOR_ROW,
 } from "../panePaste";
 
 const RULE = "─".repeat(60);
@@ -311,3 +312,17 @@ const CODEX_APPROVAL = [
   // "Press enter to confirm or esc to cancel", its dim cells left out.
   "  enteresc",
 ];
+
+describe("MENU_CURSOR_ROW", () => {
+  // The chat's 700 ms poll reads the screen cell by cell only when a row
+  // matches it, so every menu parsePaneMenu finds must have such a row.
+  it("matches a row of every menu, and no row of an idle prompt", () => {
+    const has = (rows: string[]) => rows.some((r) => MENU_CURSOR_ROW.test(r));
+    for (const menu of [ASK, MULTI, PERMISSION, CODEX_APPROVAL]) {
+      expect(parsePaneMenu(menu)).not.toBeNull();
+      expect(has(menu)).toBe(true);
+    }
+    expect(has(CLAUDE)).toBe(false);
+    expect(has(CODEX)).toBe(false);
+  });
+});

client/src/lib/panePaste.ts

@@ -27,7 +27,8 @@ interface Pane {
   paste: (text: string, submit?: boolean) => void;
   visible: () => boolean;
   key?: (data: string) => void;
-  screen?: () => PaneScreen | null;
+  /** `menuOnly`: null at once unless a row could be a menu's cursor row. */
+  screen?: (menuOnly?: boolean) => PaneScreen | null;
 }
 const panes = new Map<string, Pane>();
 let lastFocused: string | null = null;
@@ -39,7 +40,7 @@ export function registerPane(
   paste: (text: string, submit?: boolean) => void,
   visible: () => boolean = () => true,
   key?: (data: string) => void,
-  screen?: () => PaneScreen | null
+  screen?: (menuOnly?: boolean) => PaneScreen | null
 ): () => void {
   const entry = { paste, visible, key, screen };
   panes.set(runId, entry);
@@ -175,6 +176,8 @@ export type PaneMenu = {
 };
 
 const OPTION = /^ {0,4}([❯›][ \u00a0]?)? *(\d{1,2})\. +(.*)$/;
+/** A row a menu's cursor sits on (a numbered option or Submit): a menu has one. */
+export const MENU_CURSOR_ROW = /^ *[❯›][ \u00a0]* *(?:\d{1,2}\. |Submit\s*$)/;
 const SUBMIT = /^ *([❯›])?[ \u00a0]*Submit$/;
 const RULE_ROW = /^ *[─╌]{3,} *$/;
 const CHECK = /^\[([ ✔])\] *(.*)$/;
@@ -251,7 +254,9 @@ function typeRow(options: PaneMenuOption[]): number {
 /** The menu `runId`'s visible pane shows now, or null. */
 export function readRunMenu(runId: string): PaneMenu | null {
   const p = panes.get(runId);
-  const screen = p?.visible() && p.key ? p.screen?.() : null;
+  // Polled every 700 ms while a chat shows: a screen with no cursor row is
+  // answered from plain text, without reading it cell by cell.
+  const screen = p?.visible() && p.key ? p.screen?.(true) : null;
   return screen ? parsePaneMenu(screen.rows) : null;
 }