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

backend/tests/knowledge/test_enhanced_website_reader.py

@@ -1,5 +1,5 @@
 """
-Copyright 2024-2026 ChatterMate
+Copyright 2024-2026 ReplyPier
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
@@ -155,7 +155,7 @@ class TestEnhancedWebsiteReader(unittest.TestCase):
     def test_the_page_title_survives_when_it_sits_in_a_page_header(self):
         """Docs themes put the <h1> in a <header>, which selection treats as chrome.
 
-        docs.chattermate.chat lost "Quickstart: Launch Your AI Support Agent in
+        docs.replypier.site lost "Quickstart: Launch Your AI Support Agent in
         5 Minutes" that way. A page's title is its strongest retrieval signal,
         so losing it makes the page harder for an agent to find, not just
         shorter.