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>

server/__tests__/daily-cost.test.js

@@ -234,6 +234,46 @@ describe("TranscriptCache tokensByHour", () => {
   });
 });
 
+describe("writeHourly skips unchanged hours", () => {
+  const { writeHourly, forgetHourly } = require("../lib/hourly-usage");
+  const bucket = (input) => ({
+    hour: "2026-10-05T08",
+    model: "claude-opus-4-1",
+    speed: "standard",
+    geo: "",
+    tier: "standard",
+    input,
+    output: 0,
+    cacheRead: 0,
+    cacheWrite: 0,
+    cacheWrite1h: 0,
+    webSearch: 0,
+    webFetch: 0,
+    codeExec: 0,
+  });
+  const rows = () =>
+    db
+      .prepare("SELECT input_tokens FROM token_usage_hourly WHERE session_id = 'skip-hourly'")
+      .all()
+      .map((r) => r.input_tokens);
+
+  it("writes a changed hour, skips an unchanged one, and writes again once forgotten", () => {
+    session("skip-hourly", "2026-10-05T08:00:00.000Z");
+    writeHourly("skip-hourly", { a: bucket(5) });
+    assert.deepEqual(rows(), [5]);
+    writeHourly("skip-hourly", { a: bucket(9) });
+    assert.deepEqual(rows(), [9]);
+    // Deleted behind the writer's back: an unchanged bucket is not re-sent…
+    db.prepare("DELETE FROM token_usage_hourly WHERE session_id = 'skip-hourly'").run();
+    writeHourly("skip-hourly", { a: bucket(9) });
+    assert.deepEqual(rows(), []);
+    // …which is why every path that deletes hourly rows forgets them.
+    forgetHourly(["skip-hourly"]);
+    writeHourly("skip-hourly", { a: bucket(9) });
+    assert.deepEqual(rows(), [9]);
+  });
+});
+
 describe("session list cost", () => {
   it("equals the session's own cost, speed and server-tool fees included", async () => {
     session("list-fast", "2026-10-01T00:00:00.000Z");