refactor: 移除 success 字段，简化为 matched 单层判定模型

src/server/app.ts

@@ -205,7 +205,7 @@ function createTargetsResponse(store: ProbeStore): TargetStatus[] {
       recentSamples: recentSamples.map((s) => ({
         timestamp: s.timestamp,
         durationMs: s.duration_ms,
-        up: s.success === 1 && s.matched === 1,
+        up: s.matched === 1,
       })),
       stats: {
         totalChecks: stats.totalChecks,
@@ -223,7 +223,6 @@ function mapCheckResult(row: StoredCheckResult): CheckResult {
 
   return {
     timestamp: row.timestamp,
-    success: row.success === 1,
     matched: row.matched === 1,
     durationMs: row.duration_ms,
     statusDetail: row.status_detail,