bestchat V129 — stability / routes / admin performance

Changes:
1. Added clean URL routes for:
   /signup
   /forgot-password
   /reset-password
   This fixes the missing routes behind the links shown on login/signup pages.

2. Added legacy .php -> clean URL redirects for those three pages.

3. Reworked admin.php listing queries:
   - Removed the large users × pages × subscribers JOIN/GROUP BY query.
   - Counts are now calculated only for the displayed rows.
   - Removed the global subscriber aggregation that could force MySQL to create a large temporary table.
   This directly addresses the logged error: SQLSTATE[HY000] 1021 / No space left on device while writing '.(temporary)'.

4. Reworked the admin Meta-sync status summary to avoid another global GROUP BY over all pages.

5. Bumped runtime schema marker to 129 so the updated build is recognized.

6. Updated default Support links to the clean URLs.

Data safety:
- No page/subscriber/campaign deletion logic was added.
- Existing safe Facebook sync behavior is preserved: pages omitted by Meta are retained locally.

Important:
- This package is based on the V128 backup used for the review.
- Upload it as a new version after keeping the current server copy as a rollback backup.
