fix: improve worker error handling and reliability

1. Distinguish failure reasons: inspect error messages to label skipped
   packages as DOWNLOAD_FAILED, UPLOAD_FAILED, or EXTRACT_FAILED
   instead of catch-all DOWNLOAD_FAILED.

2. Detect orphaned uploads: before uploading, check if the same content
   hash already has a successful upload on the destination channel. Reuse
   the existing message ID instead of re-uploading (prevents duplicates
   when worker crashed between upload and DB write).

3. Increase timeouts: download from max(5min, GB*10min) to
   max(10min, GB*15min), upload from GB*10min to GB*15min.
   Prevents premature timeouts on slow connections.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

worker/src/db/queries.ts

@@ -62,6 +62,18 @@ export async function packageExistsByHash(contentHash: string) {
   return pkg !== null;
 }
 
+/**
+ * Find an already-uploaded package by content hash.
+ * Used to detect orphaned uploads — files that reached Telegram
+ * but whose package record was created from a previous successful run.
+ */
+export async function getUploadedPackageByHash(contentHash: string) {
+  return db.package.findFirst({
+    where: { contentHash, destMessageId: { not: null }, destChannelId: { not: null } },
+    select: { destChannelId: true, destMessageId: true },
+  });
+}
+
 /**
  * Check if a package already exists for a given source message ID
  * AND was successfully uploaded to the destination (destMessageId is set).