feat(ADR-131): HOMECORE-UI operational dashboard + BFF gateway

Complete two-tier Cognitum operator dashboard (ADR-131), served by
homecore-server at /homecore, plus the single-origin BFF gateway that
wires it to real backends.

Front-end (zero-dep vanilla TS/JS + CSS, exact Cognitum design tokens):
- All 10 panels (§4.1-4.10): dashboard, SEED fleet + detail, fleet map,
  entities (live WS subscribe_events, never polls), rooms, COGs,
  calibration wizard, events + automation builder, witness/audit, settings.
- §6 UX invariants in code: first-class provenance, prominent stale/veto/
  fragility, null(not-trained) vs withheld vs error, --mono everywhere,
  Hailo vs CPU COG distinction.
- api.js calls the gateway routes in production; mock demoted to a
  dev-only ?demo=1 fixture (no mock in prod); typed error states.
- Tests under plain node: import-graph, boot, render-smoke (22),
  interaction (3), prod-errors (13) — 5 files green; bundle ~137 KB
  (~37x smaller than HA), <2 ms/cold-render.

BFF gateway (homecore-server/src/gateway.rs, compiled + tested on Rust 1.89):
- /api/cal/* reverse-proxy to the calibration API (ADR-151).
- GET /api/homecore/rooms with the RoomState adapter (breathing->breathing_bpm,
  heartbeat:null->heart_bpm:null, injected anomaly.threshold/room_id).
- GET /api/homecore/cogs supervisor over /var/lib/cognitum/apps/.
- GET /api/homecore/appliance from /proc + TCP service probes.
- SEED-device/appliance routes return typed 503 upstream_unavailable.
- cargo test -p homecore-server = 12/12; run live (curl-verified);
  fixed a real double-v1 proxy-URL bug found during live testing.

Honest scope: W1/W2/W4/W6-appliance functional; W3/W5/W6-Hailo/federation
return typed 503 (depend on services/hardware not in this repo).

Co-Authored-By: claude-flow <ruv@ruv.net>

v2/crates/homecore-server/ui/tests/benchmark.mjs

@@ -0,0 +1,54 @@
+// Benchmark — ADR-131 §8 / ADR-126 §1.1.
+// HOMECORE exists partly because HA's frontend is a ~5 MB Lit bundle
+// (ADR-126 §1.1). This benchmark enforces a hard bundle budget and
+// measures cold render throughput for all 10 panels.
+// Run: node tests/benchmark.mjs
+import { install } from './dom-shim.mjs';
+install();
+import { readFileSync, readdirSync, statSync } from 'node:fs';
+import { resolve } from 'node:path';
+
+const ROOT = resolve(import.meta.dirname, '..');
+const BUDGET_BYTES = 250 * 1024;   // 250 KB total — vs HA's ~5 MB (20× smaller)
+
+function walk(dir) {
+  let total = 0; const rows = [];
+  for (const name of readdirSync(dir)) {
+    if (name === 'tests' || name === 'node_modules') continue;
+    const p = resolve(dir, name); const s = statSync(p);
+    if (s.isDirectory()) { const sub = walk(p); total += sub.total; rows.push(...sub.rows); }
+    else if (/\.(js|css|html|json)$/.test(name)) { total += s.size; rows.push([p.replace(ROOT + '/', ''), s.size]); }
+  }
+  return { total, rows };
+}
+
+const { total, rows } = walk(ROOT);
+rows.sort((a, b) => b[1] - a[1]);
+console.log('── Bundle size (uncompressed) ──');
+for (const [f, sz] of rows.slice(0, 8)) console.log(`  ${(sz / 1024).toFixed(1).padStart(7)} KB  ${f}`);
+console.log(`  ${'-'.repeat(40)}`);
+console.log(`  ${(total / 1024).toFixed(1).padStart(7)} KB  TOTAL across ${rows.length} files`);
+console.log(`  budget ${(BUDGET_BYTES / 1024).toFixed(0)} KB · HA baseline ~5120 KB · ratio ${(5120 * 1024 / total).toFixed(1)}× smaller`);
+
+// ── render throughput ───────────────────────────────────────────────
+const { api } = await import('../js/api.js');
+const ctx = { api, navigate() {}, params: { id: 'seed-livingroom-a1' }, onEvent() { return () => {}; }, onWs(fn) { fn({ state: 'open', lagged: false }); return () => {}; } };
+const PANELS = ['dashboard', 'fleet', 'seed-detail', 'entities', 'rooms', 'cogs', 'calibration', 'events', 'audit', 'settings'];
+const mods = {};
+for (const p of PANELS) mods[p] = (await import(`../js/panels/${p}.js`)).default;
+
+console.log('\n── Cold render throughput (avg of 50 renders each) ──');
+let worst = 0;
+for (const p of PANELS) {
+  const N = 50; const t0 = performance.now();
+  for (let i = 0; i < N; i++) { const root = document.createElement('div'); const c = await mods[p].render(root, ctx); if (typeof c === 'function') c(); }
+  const ms = (performance.now() - t0) / N;
+  worst = Math.max(worst, ms);
+  console.log(`  ${ms.toFixed(3).padStart(7)} ms/render  ${p}`);
+}
+
+console.log('');
+let exit = 0;
+if (total > BUDGET_BYTES) { console.error(`FAIL — bundle ${(total / 1024).toFixed(1)} KB exceeds ${(BUDGET_BYTES / 1024).toFixed(0)} KB budget`); exit = 1; }
+else console.log(`OK — bundle within budget; slowest panel ${worst.toFixed(2)} ms/render`);
+process.exit(exit);