Overhaul uptime monitor: time ranges, bar glow, tooltips, degraded state, immediate ping

- Add 24H/7D/30D/1Y time range selector with dynamic SQL bucketing
- Add bar glow (colored box-shadow) for up/degraded/down states
- Replace native title tooltips with positioned tooltips showing uptime % and check counts
- Add "degraded" (amber) state for buckets with mixed up/down checks
- Immediate HEAD ping on service add so status appears without 60s wait
- Taller bars (h-3 list, h-6 modal), rounded-sm, hover:scale-y-[1.3]
- Increase list bar opacity from 50% to 70%
- Add DB index on uptime_logs(service_name, timestamp)
- Extend data retention from 90 to 400 days for yearly view

lib/db.ts

@@ -42,6 +42,9 @@ export async function getDb() {
       url TEXT NOT NULL,
       created_at DATETIME DEFAULT CURRENT_TIMESTAMP
     );
+
+    CREATE INDEX IF NOT EXISTS idx_uptime_logs_service_timestamp
+      ON uptime_logs(service_name, timestamp);
   `);
 
   return db;