feat: add Telegram integration with forum topic support and creator tracking

Adds full Telegram ZIP ingestion pipeline: TDLib worker service scans source
channels for archive files, deduplicates by content hash, extracts metadata,
uploads to archive channel, and indexes in Postgres. Forum supergroups are
scanned per-topic with topic names used as creator. Filename-based creator
extraction (e.g. "Mammoth Factory - 2026-01.zip") serves as fallback.

Includes admin UI for managing accounts/channels, simplified account setup
(API credentials via env vars), auth code/password submission dialog,
package browser with creator column, and live ingestion activity tracking.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

worker/src/archive/split.ts

@@ -0,0 +1,48 @@
+import { createReadStream, createWriteStream } from "fs";
+import { stat } from "fs/promises";
+import path from "path";
+import { pipeline } from "stream/promises";
+import { childLogger } from "../util/logger.js";
+
+const log = childLogger("split");
+
+/** 2GB in bytes — Telegram's file size limit */
+const MAX_PART_SIZE = 2n * 1024n * 1024n * 1024n;
+
+/**
+ * Split a file into ≤2GB parts using byte-level splitting.
+ * Returns paths to the split parts. If the file is already ≤2GB, returns the original path.
+ */
+export async function byteLevelSplit(filePath: string): Promise<string[]> {
+  const stats = await stat(filePath);
+  const fileSize = BigInt(stats.size);
+
+  if (fileSize <= MAX_PART_SIZE) {
+    return [filePath];
+  }
+
+  const dir = path.dirname(filePath);
+  const baseName = path.basename(filePath);
+  const partSize = Number(MAX_PART_SIZE);
+  const totalParts = Math.ceil(Number(fileSize) / partSize);
+  const parts: string[] = [];
+
+  log.info({ filePath, fileSize: Number(fileSize), totalParts }, "Splitting file");
+
+  for (let i = 0; i < totalParts; i++) {
+    const partNum = String(i + 1).padStart(3, "0");
+    const partPath = path.join(dir, `${baseName}.${partNum}`);
+    const start = i * partSize;
+    const end = Math.min(start + partSize - 1, Number(fileSize) - 1);
+
+    await pipeline(
+      createReadStream(filePath, { start, end }),
+      createWriteStream(partPath)
+    );
+
+    parts.push(partPath);
+  }
+
+  log.info({ filePath, parts: parts.length }, "File split complete");
+  return parts;
+}