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

Dockerfile.frontend.prod

@@ -22,12 +22,12 @@ RUN npm install
 
 # Build the application, widget, and webclient. Use the :prod webclient build so
 # the shipped loader bakes the production fallback URL (the real backend URL is
-# resolved at runtime via window.chattermateBaseUrl / APP_CONFIG regardless).
+# resolved at runtime via window.replypierBaseUrl / APP_CONFIG regardless).
 RUN npm run build-only && \
     npm run build:widgetdocker && \
     npm run build:webclient:prod && \
     if [ ! -f dist/index.html ]; then \
-        echo "<!DOCTYPE html><html><head><meta charset='utf-8'><title>ChatterMate</title><link rel='icon' href='/favicon.ico'></head><body><div id='app'></div><script type='module' src='/src/main.ts'></script></body></html>" > dist/index.html; \
+        echo "<!DOCTYPE html><html><head><meta charset='utf-8'><title>ReplyPier</title><link rel='icon' href='/favicon.ico'></head><body><div id='app'></div><script type='module' src='/src/main.ts'></script></body></html>" > dist/index.html; \
     fi
 
 # Production stage