chore(brand): rename the product to ReplyPier

The upstream project name is gone from code, assets, docs and build
output: brand strings, domains (replypier.site and its app/api/docs/help
subdomains), env prefixes, image and network names, the widget's public
JS API (window.ReplyPier, replypierId/BaseUrl/Config/Token), CSS tokens
(--rp-*), file and directory names, and the WordPress plugin package.

- widget loader is now webclient/replypier.min.js; both bundles rebuilt
  from source (backend/assets/widget.{js,css}, frontend/public/webclient)
- NOTICE, llms.txt, CONTRIBUTING, HELP_CENTER_INFRA and config.dev.js
  rewritten rather than string-swapped; the demo config no longer ships
  the previous vendor's Firebase/Razorpay/Google keys
- new migration replypier_ai_model_001 adds REPLYPIER to the managed
  AIModelType and rewrites pre-rename rows
- local compose project, database, role and volume renamed; LOCAL_DEPLOY
  documents carrying the old local data over

e2e/package.json

@@ -1,8 +1,8 @@
 {
-  "name": "chattermate-e2e",
+  "name": "replypier-e2e",
   "private": true,
   "type": "module",
-  "description": "End-to-end tests for ChatterMate (dashboard, widget, backend) — see AUTHORING.md",
+  "description": "End-to-end tests for ReplyPier (dashboard, widget, backend) — see AUTHORING.md",
   "engines": {
     "node": ">=22.18"
   },