fix(service): allow desktop app origins in Buzz template CORS

[Onnokh]

Changes

• Add the two Tauri origins (tauri://localhost, http://tauri.localhost) to
  BUZZ_CORS_ORIGINS in the Buzz template, so the Buzz desktop app can connect
  to the deployed relay.

Issues

• Fixes [Bug]: Buzz one-click template blocks the Buzz desktop app (CORS) #11044
• Supersedes fix(service): allow desktop app origins in Buzz template CORS #11045, which the quality bot closed. That diff also touched the
  two generated service-templates JSON files, which are a blocked path for
  contributors; this one changes the template only.

Category

• Bug fix
• Improvement
• New feature
• Adding new one click service
• Fixing or updating existing one click service

AI Assistance

• AI was NOT used to create this PR
• AI was used (please describe below)

If AI was used:

• Tools used: Claude Code
• How extensively: Used to trace the cause and prepare the patch. The desktop
  app failed with "Load failed" against my own self-hosted Buzz relay. The two
  origins come from Buzz's own source, which documents them in its relay config
  and hardcodes the same pair in the desktop media proxy. Verified on a live
  deployment before opening this PR. Human-reviewed.

Testing

Deployed Buzz behind Coolify's proxy and compared CORS responses before and
after the change:

Origin	before	after
the relay's own https origin	allowed	allowed
tauri://localhost	no access-control-allow-origin header	allowed

The desktop app went from "Load failed" to connecting normally, with no other
change. The relay parses the variable as a comma-separated list, so the existing
web origin is unaffected.

Contributor Agreement

Important

• I have read and understood the contributor guidelines. If I have failed to follow any guideline, I understand that this PR may be closed without review.
• I have searched existing issues and pull requests (including closed ones) to ensure this isn't a duplicate.
• I have tested all the changes thoroughly with a local development instance of Coolify and I am confident that they will work as expected when a maintainer tests them.