chore: settle product naming across app, widget and deployments

One word everywhere: ReplyPier in UI copy, package and image names, the
replypier.site domains (app/api/docs/help), REPLYPIER_* settings and the
--rp-* design tokens.

- public widget API is window.ReplyPier with replypierId / replypierBaseUrl /
  replypierConfig / replypierToken, loader at webclient/replypier.min.js;
  both bundles rebuilt from source
- NOTICE, llms.txt, CONTRIBUTING, HELP_CENTER_INFRA and the demo runtime
  config rewritten; the demo config ships no third-party keys
- migration adds the ReplyPier managed model value to the AI model enum
- local compose project, database, role, volume and Docker network carry the
  same name

backend/app/crm/mapping.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.
@@ -109,7 +109,7 @@ def build_note_body(payload: LeadPayload) -> str:
     render notes as HTML, so plain newlines would collapse and run the summary
     into the header. Labelled lines keep the AI summary unmistakable; dynamic
     values are escaped."""
-    lines = ["<b>Lead captured by ChatterMate</b>"]
+    lines = ["<b>Lead captured by ReplyPier</b>"]
     if payload.summary:
         lines.append(f"<b>AI summary:</b> {html.escape(payload.summary)}")
     for label, value in (payload.custom_fields or {}).items():