feat(cloudflare): 完成隧道接入、运维与 P0 体验优化

migrations/036_cf_health.sql

@@ -0,0 +1,13 @@
+-- Cloudflare 隧道健康事件：只记录状态变化，供巡检通知与公开状态页计算 24h 可用率。
+CREATE TABLE IF NOT EXISTS cf_health_events (
+    id        INTEGER PRIMARY KEY AUTOINCREMENT,
+    tunnel_id INTEGER NOT NULL,
+    domain    TEXT NOT NULL,
+    state     TEXT NOT NULL,
+    reason    TEXT NOT NULL DEFAULT '',
+    detail    TEXT NOT NULL DEFAULT '',
+    at        TEXT NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_cf_health_events_lookup ON cf_health_events(tunnel_id, domain, id);
+CREATE INDEX IF NOT EXISTS idx_cf_health_events_at ON cf_health_events(at);