feat: add preview management, channel controls, invite polish, and recovery

- Auto-extract preview images from ZIP/RAR/7z archives during ingestion
- Upload custom preview images via package drawer
- Select preview from archive contents with on-demand extraction UI
- Manually add Telegram channels by t.me link, username, or invite link
- Invite code UX: bulk create, copy link, usage tracking, delete confirm
- Incomplete upload recovery: verify dest messages on worker startup
- Rebuild package DB by scanning destination channel with live progress

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

worker/src/worker.ts

@@ -34,6 +34,7 @@ import { getChannelMessages, downloadFile, downloadPhotoThumbnail } from "./tdli
 import type { DownloadProgress, ChannelScanResult } from "./tdlib/download.js";
 import { isChatForum, getForumTopicList, getTopicMessages } from "./tdlib/topics.js";
 import { matchPreviewToArchive } from "./preview/match.js";
+import { pickPreviewFile, extractPreviewImage } from "./preview/extract.js";
 import { groupArchiveSets } from "./archive/multipart.js";
 import type { ArchiveSet } from "./archive/multipart.js";
 import { extractCreatorFromFileName, extractCreatorFromChannelTitle } from "./archive/creator.js";
@@ -971,6 +972,23 @@ async function processOneArchiveSet(
       previewMsgId = matchedPhoto.id;
     }
 
+    // ── Fallback: extract preview image from inside the archive ──
+    if (!previewData && entries.length > 0 && archiveSet.type !== "DOCUMENT") {
+      const previewEntry = pickPreviewFile(entries);
+      if (previewEntry) {
+        accountLog.debug(
+          { fileName: archiveName, previewFile: previewEntry.path },
+          "Attempting to extract preview image from archive"
+        );
+        const archiveTypeForExtract = archiveSet.type === "7Z" ? "SEVEN_Z" as const : archiveSet.type as "ZIP" | "RAR";
+        previewData = await extractPreviewImage(
+          tempPaths[0],
+          archiveTypeForExtract,
+          previewEntry.path
+        );
+      }
+    }
+
     // ── Resolve creator: topic name > filename extraction > channel title > null ──
     const creator = topicCreator
       ?? extractCreatorFromFileName(archiveName)