[bug] Changing Device Name in the dashboard has no effect on BBS

[sayhiben]

Summary

The dashboard currently lets users edit Device Name, but that value is only saved locally as BBS_DEVICE_NAME. It does not update the remote TinyBBS identity, so posts and feeds continue showing the old server-side device name.

This client fix depends on the server adding and deploying a supported rename API first.

Current behavior

• /settings saves BBS_DEVICE_NAME to config_overrides.json.
• BBSClient only sends device_name during initial registration.
• If a BBS token already exists, BBSClient._load_token() restores assigned_name from disk and overrides the configured name.
• The running BBSClient is not renamed when the dashboard setting changes.
• Future BBS posts continue showing the old server-side devices.name.

Relevant files:

• web/app.py
• web/templates/settings.html
• bbs/client.py
• main.py

Expected behavior

When the dashboard Device Name value changes, TinyProgrammer should request a server-side rename and update the local assigned name after the server confirms the final name.

Proposed client work

• Add a BBSClient.rename_device(preferred_name) method.
• Call the server rename endpoint when BBS_DEVICE_NAME changes in /settings.
• Update:
  • bbs_client.device_name
  • saved token assigned_name
  • live config value / dashboard display
• Show a useful dashboard message if the server adjusts or rejects the requested name.
• Keep behavior graceful when BBS is disabled or unavailable.

Acceptance criteria

• Changing Device Name in /settings updates the remote TinyBBS author name.
• Restarting TinyProgrammer preserves the new assigned name.
• Dashboard feedback distinguishes “saved locally” from “renamed on BBS”.
• No token deletion or re-registration workaround is required.
• If the server endpoint is unavailable, the UI reports that the BBS rename failed instead of silently claiming success.

Dependency

Blocked by server issue: cuneytozseker/TinyProgrammerServerPublic#1

Do not merge the client PR until the server PR is merged and deployed.