feat(orchestrator): S3 generated SVG faces whose mouths move while speaking

Requirement 001 phase 6, S3:

- faces.js derives a face from the agent's stable key (its session id,
  or name:<name> without a session), so a rename keeps the face: shape
  4, colour 7, eyes 5, brows 4, mouth 5, hair or headwear 6, accessory 5,
  84,000 combinations. It emits constant SVG tags and attributes only.
- The emoji avatar is gone: popup, Orbit and Chord nodes, the radio
  view, stream and palette draw the SVG face (the 3D views keep their
  marker).
- While the radio reads an agent's message, its faces carry the class
  speaking and the mouth runs the talk keyframes; a silent face does
  not move, and prefers-reduced-motion stops the mouth.

Evidence: make test 673 OK, ruff and markdownlint clean
(/tmp/s3-make-test-1.log); e2e 20 OK in Chromium and Firefox, none
skipped (/tmp/s3-e2e-3.log); screenshots
/tmp/orchestrator-phase4-shots/*-speaking.png; MEDUSA 13 files, 2
findings ("PLA" in "templates", the UI call openAgent) accepted after
an independent skeptic that found no markup sink or selector injection
in the face code.

🎯 Fix: 94 %
💥 Break: 3 %
💸 Cost: 100 %
⏱️ Time: –
🛡️ Security: 100 %
🏆 Score: 91
🚦 Gate: ✅ 90/5, cost and time <= 100, security 100 %

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

orchestrator/templates/page-graph-layout.js

@@ -137,7 +137,7 @@
     },
     s("title", {}, `${node.label} · ${NODE_KINDS[node.kind]}${node.parent ? ` of ${labelOf(node.parent)}` : ""}${tasks}`),
     s("circle", {r}),
-    node.kind === "subagent" ? null : s("text", {class: "initial", "text-anchor": "middle", dy: "0.35em"}, node.label.slice(0, 1).toUpperCase()),
+    node.kind === "subagent" ? null : s("g", {class: "face-art", transform: `translate(${-r} ${-r}) scale(${(2 * r) / Faces.SIZE})`}, faceParts(node.id)),
     caption(node, at, r, gap));
   }