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/utils/test_offtopic_exercise.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.
@@ -68,7 +68,7 @@ class TestCatchesTheAbuse:
         assert detect_offtopic_exercise(PROD_BRIEF) is True
 
     def test_still_caught_when_org_name_is_known(self):
-        assert detect_offtopic_exercise(PROD_BRIEF, ["ChatterMate"]) is True
+        assert detect_offtopic_exercise(PROD_BRIEF, ["ReplyPier"]) is True
 
 
 class TestPrecision:
@@ -121,5 +121,5 @@ class TestThresholds:
         assert detect_offtopic_exercise(text) is False
 
     def test_org_name_mention_anchors_it(self):
-        text = PROD_BRIEF + "\nWe need this for our ChatterMate integration."
-        assert detect_offtopic_exercise(text, ["ChatterMate"]) is False
+        text = PROD_BRIEF + "\nWe need this for our ReplyPier integration."
+        assert detect_offtopic_exercise(text, ["ReplyPier"]) is False