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>

tests/test_hub_page.py

@@ -11,7 +11,7 @@ from pathlib import Path
 from unittest import mock
 
 from hub_case import HubCase
-from hub_support import AMBIENCE, NAV, POPUP, SPACE, VOICE
+from hub_support import AMBIENCE, FACES, NAV, POPUP, SPACE, VOICE
 from kvb_orchestrator import exchange
 
 
@@ -63,9 +63,9 @@ class TestHubPage(HubCase):
         self.assertEqual((state["reviews"][0]["title"], state["reviews"][0]["notes"]), ("<script>alert(1)</script>", "</pre><script>alert(2)</script>"))
         self.assertEqual((state["register"][0]["title"], state["radio"][0]["from"]), ("<script>alert(3)</script>", "<img src=x>"))
 
-    def test_the_index_scripts_parse_and_embed_the_ambience_voice_nav_popup_and_space_modules(self):
+    def test_the_index_scripts_parse_and_embed_the_ambience_voice_nav_popup_faces_and_space_modules(self):
         html = self.index()
-        for module in (AMBIENCE, VOICE, NAV, POPUP, SPACE):
+        for module in (AMBIENCE, VOICE, NAV, POPUP, FACES, SPACE):
             with self.subTest(module=module.name):
                 self.assertIn(module.read_text(encoding="utf-8").strip(), html)
         scripts = re.findall(r'<script nonce="[^"]+">(.*?)</script>', html, re.DOTALL)
@@ -74,7 +74,7 @@ class TestHubPage(HubCase):
         page.write_text("\n;\n".join(scripts), encoding="utf-8")
         done = subprocess.run(["node", "--check", str(page)], capture_output=True, text=True, timeout=60, check=False)
         self.assertEqual(done.returncode, 0, done.stderr)
-        for module in (AMBIENCE, VOICE, NAV, POPUP, SPACE):
+        for module in (AMBIENCE, VOICE, NAV, POPUP, FACES, SPACE):
             with self.subTest(module=module.name):
                 done = subprocess.run(["node", "--check", str(module)], capture_output=True, text=True, timeout=60, check=False)
                 self.assertEqual(done.returncode, 0, done.stderr)