Deadline Countdown Multi-Site Aggregator

WHAT IT DOES This script adds a floating, draggable overlay to your browser that displays all your upcoming deadlines with real-time countdown timers showing days, hours, minutes, and seconds remaining. Each deadline is color-coded by urgency—green (calm), yellow (warning), red (urgent), or blue (far off)—so you can instantly see which tasks need immediate attention. A badge shows the count of urgent deadlines, and optional desktop notifications alert you when deadlines approach within a configurable lead time. Perfect for project managers, students, freelancers, and anyone juggling multiple deadlines across different projects. WHERE IT RUNS The script works on any website—browsing, working, or researching. The overlay stays visible as you navigate between pages, providing a persistent deadline reference. It works on any website regardless of framework, and per-site memory remembers your overlay position on each domain. HOW TO USE After installation, the overlay appears automatically if you have any deadlines set. Open the panel to configure: add deadlines via JSON array with name, date (YYYY-MM-DD), time (HH:MM), optional note, and notification toggle; choose overlay position, opacity, and dark/light theme; set urgency thresholds (green, yellow, red in days); enable or disable seconds display and the urgent badge; configure notification lead time in hours; and enable per-site memory. The overlay updates every second in real time. Click the badge to toggle the overlay, or the ✕ button to hide it. TECHNICAL MECHANISM The script uses a multi-stage deadline tracking pipeline. First, it loads deadlines from GM_setValue as a JSON array with name, date, time, note, and notify flag. Second, it calculates time remaining for each deadline using `new Date()` with the parsed date and time, computing the difference in milliseconds. Third, it converts the difference to days, hours, minutes, and seconds using integer arithmetic. Fourth, it determines urgency by comparing days remaining to configurable thresholds—red (