~anthropic/claude-sonnet-latest → B (8:2)

Side B removes a fragile, over-engineered 1800-line keystroke-parsing state machine (with race conditions requiring a whole Playwright test harness) and replaces it with a small, correct, testable paste-and-go URL parser plus simplified UI/JS/tests — a real simplification and bugfix with lasting architectural value. Side A is purely CSS polish (padding, borders, focus outlines) across two theme files, which is cosmetic churn with no functional or structural improvement.