Maintenance release.

• Support page: separate links for bug reports and for questions/discussions
• Support page now links to this official Firefox Add-ons listing
• Debug panel shows Firefox-specific details when debug mode is enabled
• Internal: hardened the automated build pipeline (CI actions pinned to audited revisions) and stabilized the automated Firefox test suite

No changes to cookie-cleaning behavior, permissions, or data handling. The extension still collects no data.