DEV-C P2: SPA churn was re-running the full scan many times per second.
Trailing-edge debounce coalesces bursts so scan() runs at most once per
quiet 200ms window.
No test harness exists for content/detector.ts on this branch; relies
on manual verification on a real SPA page.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Login form detector using password field + username heuristics,
native value setter fill for React/Vue compatibility, inline "id" icon
injection with autofill candidate picker, and MutationObserver for SPA support.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>