Rentiva v4.64.1 — Dark Mode Toggle Field Clobber Fix

Fixes the admin panel's quick Dark Mode switch silently blanking Support Phone/Hours/Email and resetting Brand Name, and cleans up a residual settings-pollution artifact left behind by an older migration.

Fixed

• Dark Mode toggle silently blanked General/Site-Info settings. The admin panel's quick Dark Mode AJAX switch re-ran the entire General tab's sanitizer with only the dark-mode value present, silently blanking Support Phone, Support Hours, and Support Email, and resetting Brand Name back to the site title on every toggle. It now updates only the dark mode setting.
• Residual settings-pollution cleanup. A one-time cleanup added in v4.27.2 for a historical "Run All Diagnostics" data-pollution bug (which could leave Brand Name and similar text fields saved as the literal value "1") never re-ran on installs where its completion flag had already been stamped before the pollution actually occurred. A second cleanup pass now catches any installs still carrying the old pollution.