Rebrand product to Hesychia (hesychia.ai) (#29) (#32)

## Summary
- Closes #29
- Rename user-facing product from AIML Operations chat to **Hesychia** (headers, sidenav brand, footer, ToS welcome, sample page)
- Update page metadata (`title`, description, Open Graph, `manifest.json` app name)
- Point README / env comments at **hesychia.ai**; keep live API hosts and deploy webroots until infra cutover

## Android display name
Capacitor tree is not on `master` yet ([#28](#28)). Display name / `appName` → **Hesychia** pushed on `ship-android-capacitor-20` so it lands with that wrap. Package id stays `com.aimloperations.chat` (Play identity; rename later if desired).

## Out of scope (per issue)
- New logo artwork (#30)
- Backend system-prompt identity (`chat_backend` #20)

## Test plan
- [ ] Web UI shows **Hesychia** in header / sidenav / footer (no old product name)
- [ ] Browser tab title and PWA manifest name are Hesychia
- [ ] Footer still credits AI ML Operations, LLC as developer
- [ ] `npm run test:ci` (Footer test updated)
- [ ] After #28 merges: Android launcher / activity title shows HesychiaReviewed-on: #32

llm-fe/public/manifest.json

@@ -1,6 +1,6 @@
 {
-  "short_name": "Chat by AI ML Operations. LLC",
-  "name": "Chat by AI ML Operations, LLC",
+  "short_name": "Hesychia",
+  "name": "Hesychia",
   "icons": [
     {
       "src": "favicon.ico",