fix: make import lock unique per attempt + release in finally

- Add timestamp to lock key to prevent blocking retries
- Wrap create logic in try-finally to always release lock
- Reduce lock TTL from 30min to 5min

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/modules/document-import/document-import.service.ts

@@ -22,13 +22,15 @@ export class DocumentImportService {
   }) {
     this.logger.log(`createImport called: userId=${dto.userId}, kbId=${dto.knowledgeBaseId}, fileName=${dto.fileName}, sourceType=${dto.sourceType}`);
     try {
-      const lockKey = `lock:document-import:${dto.fileName || Date.now()}`;
-      this.logger.log(`Attempting Redis lock: ${lockKey}`);
-      const lockToken = await this.redis.lock(lockKey, 1800);
+      // Use unique lock key per upload attempt to avoid blocking retries
+      const lockKey = `lock:document-import:${dto.fileName || 'file'}:${Date.now()}`;
+      this.logger.log(`Acquiring lock: ${lockKey}`);
+      const lockToken = await this.redis.lock(lockKey, 300); // 5 min TTL, enough for one upload
       if (!lockToken) {
         throw new Error('相同文件正在导入中，请稍候');
       }
 
+      try {
         this.logger.log(`Creating DB record...`);
         const job = await this.repository.create(dto);
         this.logger.log(`DB record created: ${job.id}`);
@@ -47,9 +49,10 @@ export class DocumentImportService {
         });
         this.logger.log(`Job enqueued: ${job.id}`);
 
-      await this.redis.unlock(lockKey, lockToken);
-
         return { jobId: job.id, status: 'queued' };
+      } finally {
+        await this.redis.unlock(lockKey, lockToken);
+      }
     } catch (err: any) {
       this.logger.error(`createImport failed: ${err.message}`, err.stack);
       throw err;