ClearChat Home v1.6.2 — Release Candidate Cleanup

Focused on final Home cleanup before a public release candidate:
- cleaner spacing and alignment polish
- improved mobile responsiveness groundwork
- logo/text alignment cleanup
- backup table cleanup
- installer/help wording polish
- reduced leftover temp/update clutter in packaged builds
- fresh-install readiness improvements

Recommended test path:
1. Fresh install on a clean server or clean folder.
2. Confirm admin login and settings save.
3. Test visitor chat, admin reply, close/end chat.
4. Test avatar/logo upload with images under the internal limit.
5. Test manual backup and restore on a non-production test install.
6. Treat ZIP updater as experimental until fully validated.
