Rentiva v4.64.3 — Full Dark Mode Contrast Audit

A full contrast audit across every Settings tab, fixing roughly 15 more dark-mode readability issues beyond the previous patch.

Fixed

• Full dark-mode contrast audit. The v4.64.2 fix only addressed 3 isolated spots; this release fixes ~15 more across all 16 Settings tabs: the Lite-upgrade notice link, page-header buttons (Belgeler / Bu Sekmeyi Sıfırla / Konum Yönetimi / Rotaları Yönet), System Status cards, the "Issue New Credentials" and "Cleanup Dashboard" boxes, accordion sections and their labels, data tables (REST API reference, DB cleanup history), <code> tags, and an entire tab (Bildirim Şablonları) whose custom template wasn't covered by any prior dark-mode rule.
• Light-mode regression fix. Two Database Cleanup cards lost their card styling in light mode as a side effect of the dark-mode work above; restored.

Verified with an automated WCAG contrast scanner across all 16 Settings tabs (0 remaining failures) plus two rounds of independent code review.