perf: v2.5.10 — ready for 10+ concurrent users, leaner locally

Measured on a copy of a real 1.2 GB / 253K-event database, 10 simulated
browsers + 10 hooks/s for 90 s: event-loop delay p99 1239 ms → 32 ms (max
2.0 s → 94 ms), 266 failed requests → 0, 74 → 111 requests/s served, server
RSS 633 → 346 MB. Entry bundle 975 KB raw → 394 KB (106 KB brotli).

Server
- /api/analytics: the events-table scans run in the read worker
  (scoped-stats eventAggregates, read-pool job analyticsEvents); runRead takes
  maxAgeMs — analytics 10 s, /api/workflows 30 s — keyed by the args
- /api/workflows/skill-usage: +event_type and a tool_name range instead of
  LIKE, so it uses idx_events_tool (784 ms → a few ms)
- idx_events_session_type_tool (session_id, event_type, tool_name,
  created_at) replaces idx_events_session_type: covering reads for session
  stats, the hook dedupes and the import resume point (1.2 s → 20 ms); 64 MB
  cache_size and 256 MB mmap_size on both connections
- WAL: the server sets wal_autocheckpoint = 0 and checkpoints PASSIVE every
  DASHBOARD_WAL_CHECKPOINT_MS (5 s) from the read worker's own writable
  connection; a failed checkpoint restores the automatic one (hook COMMIT p95
  109 ms → 15 ms at 100 hooks/s)
- tmux: one list-sessions answers a whole GET /api/lanes and the heal beat
  (liveSessions), shared for 1 s and cleared by this process's new/kill —
  GET /api/run's sync spawns had blocked 60 s of a 90 s run; the heal beat
  skips tmux when nothing runs; attach options chained into 2 spawns
- hooks: TurnDuration/APIError deduped against one read per hook instead of a
  query per transcript entry (23 ms/hook on a 763-turn session); one lane
  scan per hook; hourly upserts skip rows that did not grow; frames are sent
  after the transaction commits (and after the pane binding); new_event
  carries its row id; a split pane's (slot 1–9) hooks no longer rebind the
  lane's session_id
- watchdog liveness probe runs ps asynchronously; transcript newline scan via
  indexOf; startup subagent backfill fingerprints the files it already checked
- pty attach: backpressure (pause past 1 MB unsent, resume under 256 KB)
- static: hashed assets served from their pre-compressed .br/.gz sibling

Client
- hidden tabs neither refetch on WS events nor poll (useLiveRefresh, panes,
  lane cards, git header, changes panel, settings); no per-tab hourly
  /updates/check (the server already checks)
- refetch storms throttled (workspace tree/session list 3 s, /api/run only on
  a run-key change, notification pane lookup only when shown); WS reconnect
  jitter; terminal retry backoff 1.5 → 30 s, stops on 1008
- heavier throttles for aggregates (15 s) and detail views; Monitor keepIfSame;
  GET in-flight dedupe in request()
- lazy Dashboard/History, xterm (with the first terminal), lane modals, Sagi
  (only while enabled); only the active locale loads; Workspace chunk
  prefetched on a /workspace deep link
- Sagi: no work while disabled, pupil via CSS variables, memo avatar
- build: .br/.gz siblings, sourcemap hidden; service worker no longer caches
  /assets/ (cache v3 drops the old one)

Tests: scripts/test-server.js drops the GIT_DIR-family variables a hook
exports, so a suite run from a linked worktree's pre-commit can no longer
commit into the real repository or set core.bare.

Docs: ARCHITECTURE, DATABASE, API, DEPLOYMENT, client README,
docs/plans/perf/README.md (audit, checklist, results).

client/src/components/Sagi/SagiAvatar.tsx

@@ -36,7 +36,7 @@
  * - `skills/file-headers/` — mandatory `@author` header policy.
  * ============================================================================= */
 
-import { useEffect, useRef, useState } from "react";
+import { memo, useEffect, useRef } from "react";
 import type { Mood } from "./brain";
 
 interface SagiAvatarProps {
@@ -76,10 +76,21 @@ if (typeof window !== "undefined") {
   });
 }
 
-export function SagiAvatar({ mood, reducedMotion, size = 68 }: SagiAvatarProps) {
+// The pupil offset is written as CSS variables on the root, never as state, so
+// following the cursor costs no React render.
+function setPupil(el: SVGSVGElement | null, x: number, y: number) {
+  el?.style.setProperty("--sagi-px", `${x}px`);
+  el?.style.setProperty("--sagi-py", `${y}px`);
+}
+
+// memo: Sagi re-renders on every brain tick; the avatar only on mood/size/motion.
+export const SagiAvatar = memo(function SagiAvatar({
+  mood,
+  reducedMotion,
+  size = 68,
+}: SagiAvatarProps) {
   const rootRef = useRef<SVGSVGElement | null>(null);
   const rafRef = useRef<number>();
-  const [pupil, setPupil] = useState({ x: 0, y: 0 });
 
   // Pupils follow the cursor whenever motion is allowed and the eyes are open.
   // (Only `sleeping` closes them by intent; `disconnected` hides the open-eye
@@ -89,7 +100,7 @@ export function SagiAvatar({ mood, reducedMotion, size = 68 }: SagiAvatarProps)
 
   useEffect(() => {
     if (!tracking) {
-      setPupil({ x: 0, y: 0 });
+      setPupil(rootRef.current, 0, 0);
       return;
     }
 
@@ -105,7 +116,7 @@ export function SagiAvatar({ mood, reducedMotion, size = 68 }: SagiAvatarProps)
       // Normalize then clamp to the eye socket range.
       const nx = (dx / dist) * Math.min(1, dist / 240);
       const ny = (dy / dist) * Math.min(1, dist / 240);
-      setPupil({ x: nx * MAX_PUPIL_SHIFT, y: ny * MAX_PUPIL_SHIFT });
+      setPupil(el, nx * MAX_PUPIL_SHIFT, ny * MAX_PUPIL_SHIFT);
     };
 
     // Immediately aim at the last-known cursor (next frame, so layout is ready)
@@ -202,7 +213,7 @@ export function SagiAvatar({ mood, reducedMotion, size = 68 }: SagiAvatarProps)
       <g className="sagi-eye sagi-eye-left">
         <g
           className="sagi-eye-track"
-          style={{ transform: `translate(${pupil.x}px, ${pupil.y}px)` }}
+          style={{ transform: "translate(var(--sagi-px, 0px), var(--sagi-py, 0px))" }}
         >
           <g className="sagi-eye-blink">
             <path
@@ -226,7 +237,7 @@ export function SagiAvatar({ mood, reducedMotion, size = 68 }: SagiAvatarProps)
       <g className="sagi-eye sagi-eye-right">
         <g
           className="sagi-eye-track"
-          style={{ transform: `translate(${pupil.x}px, ${pupil.y}px)` }}
+          style={{ transform: "translate(var(--sagi-px, 0px), var(--sagi-py, 0px))" }}
         >
           <g className="sagi-eye-blink">
             <path
@@ -792,4 +803,4 @@ export function SagiAvatar({ mood, reducedMotion, size = 68 }: SagiAvatarProps)
       </g>
     </svg>
   );
-}
+});