feat: 测活覆盖全部代理（含死记录），拨活即复活

ListProxiesDue 去掉 alive=1 限制：死代理每小时也重测，协议级握手
成功就 MarkProxyAlive 复活（fail_count 清零），不再只能等同步时
重新出现在源列表才复活。

附带：提取页加「带协议前缀」开关，复制链接自动带 fmt=url。

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

backend/internal/db/queries.sql

@@ -208,7 +208,7 @@ WHERE id = ?;
 DELETE FROM proxies WHERE id = ?;
 
 -- name: ListProxiesDue :many
-SELECT id, ip, port, protocols, fail_count FROM proxies WHERE alive = 1 AND last_checked_at < ? ORDER BY last_checked_at LIMIT 20000;
+SELECT id, ip, port, protocols, fail_count FROM proxies WHERE last_checked_at < ? ORDER BY last_checked_at LIMIT 20000;
 
 -- name: MarkProxyAlive :exec
 UPDATE proxies SET last_checked_at = ?, alive = 1, fail_count = 0, last_alive_at = ?, latency = ? WHERE id = ?;

backend/internal/db/queries.sql.go

@@ -1887,7 +1887,7 @@ func (q *Queries) ListPendingPayOrders(ctx context.Context) ([]PayOrder, error)
 }
 
 const listProxiesDue = `-- name: ListProxiesDue :many
-SELECT id, ip, port, protocols, fail_count FROM proxies WHERE alive = 1 AND last_checked_at < ? ORDER BY last_checked_at LIMIT 20000
+SELECT id, ip, port, protocols, fail_count FROM proxies WHERE last_checked_at < ? ORDER BY last_checked_at LIMIT 20000
 `
 
 type ListProxiesDueRow struct {

backend/internal/service/proxy.go

@@ -297,8 +297,8 @@ func runProxySync(ctx context.Context, st *store.Store) {
 		sync.Total, sync.Added, sync.Updated, sync.Removed, failed)
 }
 
-// runProxyCheck 测活一轮：取距上次检测超过阈值的存活代理，并发 TCP 拨测；
-// 连不上即标记为死（alive=0），死记录超过保留期后物理清除。
+// runProxyCheck 测活一轮：取距上次检测超过阈值的全部代理（含死记录，拨活即复活），
+// 并发协议级拨测；连不上即标记为死（alive=0），死记录超过保留期后物理清除。
 func runProxyCheck(ctx context.Context, st *store.Store) {
 	if !proxyChecking.CompareAndSwap(false, true) {
 		return