feat: fix multi-part archive forwarding and add kickstarter package linking

Multi-part send fix:
- Add destMessageIds BigInt[] to Package schema with backfill migration
- Worker uploadToChannel now returns all message IDs, stored in DB
- Bot forwards all parts of multi-part archives (not just the first)
- Add retry logic for upload rate limits (429) and download stalls

Kickstarter package linking:
- Add package search/linking queries and API routes
- Add PackageLinkerDialog with search + checkbox selection
- Add "Link Packages" and "Send All" actions to kickstarter table
- Add sendAllKickstarterPackages server action

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

bot/src/db/queries.ts

@@ -122,6 +122,9 @@ export async function getPendingSendRequest(requestId: string) {
           archiveType: true,
           destChannelId: true,
           destMessageId: true,
+          destMessageIds: true,
+          isMultipart: true,
+          partCount: true,
           previewData: true,
           sourceChannel: { select: { title: true, telegramId: true } },
         },

bot/src/send-listener.ts

@@ -7,7 +7,7 @@ import {
   findMatchingSubscriptions,
   getGlobalDestinationChannel,
 } from "./db/queries.js";
-import { copyMessageToUser, sendTextMessage, sendPhotoMessage } from "./tdlib/client.js";
+import { copyMessageToUser, copyMultipleMessagesToUser, sendTextMessage, sendPhotoMessage } from "./tdlib/client.js";
 import { sleep } from "./util/flood-wait.js";
 
 const log = childLogger("send-listener");
@@ -154,11 +154,25 @@ async function processSendRequest(requestId: string): Promise<void> {
     }
 
     // Forward the actual archive file(s) from destination channel
-    await copyMessageToUser(
-      destChannel.telegramId,
-      pkg.destMessageId,
-      targetUserId
-    );
+    const messageIds = pkg.destMessageIds as bigint[] | undefined;
+    if (messageIds && messageIds.length > 1) {
+      log.info(
+        { requestId, parts: messageIds.length },
+        "Sending multi-part archive"
+      );
+      await copyMultipleMessagesToUser(
+        destChannel.telegramId,
+        messageIds,
+        targetUserId
+      );
+    } else {
+      // Single part or legacy (no destMessageIds populated)
+      await copyMessageToUser(
+        destChannel.telegramId,
+        pkg.destMessageId,
+        targetUserId
+      );
+    }
 
     await updateSendRequest(requestId, "SENT");
     log.info({ requestId }, "Send request completed successfully");

bot/src/tdlib/client.ts

@@ -121,6 +121,25 @@ export async function copyMessageToUser(
   }, fileName);
 }
 
+/**
+ * Send multiple document messages from a channel to a user's DM.
+ * Used for multi-part archives where each part is a separate Telegram message.
+ * Sends parts sequentially with a small delay to avoid rate limits.
+ */
+export async function copyMultipleMessagesToUser(
+  fromChatId: bigint,
+  messageIds: bigint[],
+  toUserId: bigint
+): Promise<void> {
+  for (let i = 0; i < messageIds.length; i++) {
+    await copyMessageToUser(fromChatId, messageIds[i], toUserId);
+    // Small delay between parts to avoid rate limits
+    if (i < messageIds.length - 1) {
+      await new Promise((resolve) => setTimeout(resolve, 1000));
+    }
+  }
+}
+
 /**
  * Send a message and wait for Telegram to confirm delivery.
  * Returns when updateMessageSendSucceeded fires for the temp message.