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/scripts/encrypt_chat_at_rest.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.

backend/scripts/preload_models.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 """
-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.

backend/scripts/prune_offsite_pages.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.

backend/scripts/rechunk_knowledge.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.

backend/scripts/test_lead_capture_prompt.py

@@ -114,7 +114,7 @@ def get_model_config():
 
 def build_agent(model_type: str, api_key: str, model_name: str) -> Agent:
     # Same construction shape as production: create_model() (agno OpenAIChat for
-    # OPENAI/CHATTERMATE) + ChatResponse response_model + structured outputs. No
+    # OPENAI/REPLYPIER) + ChatResponse response_model + structured outputs. No
     # tools/knowledge here — we're testing the conversational lead-ask behaviour.
     return Agent(
         model=create_model(model_type, api_key, model_name, max_tokens=1000),