Add StringSession support and generator

scripts/generate-session-string.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python3
+"""
+Generate a Telethon StringSession for OverUB.
+"""
+
+import asyncio
+import os
+from getpass import getpass
+
+from telethon import TelegramClient
+from telethon.sessions import StringSession
+
+
+async def generate() -> None:
+    api_id = os.getenv("OVERUB_API_ID") or os.getenv("API_ID")
+    api_hash = os.getenv("OVERUB_API_HASH") or os.getenv("API_HASH")
+    if not api_id or not api_hash:
+        print("API_ID/API_HASH required (set OVERUB_API_ID/OVERUB_API_HASH or API_ID/API_HASH).")
+        return
+    try:
+        api_id = int(api_id)
+    except ValueError:
+        print("API_ID must be an integer")
+        return
+
+    print("Starting session generation. You will be prompted to log in.")
+    client = TelegramClient(StringSession(), api_id, api_hash)
+    await client.start()
+    session_string = client.session.save()
+    await client.disconnect()
+
+    print("\nSession string:")
+    print(session_string)
+    print("\nSet this in config/config.yml as bot.session_string or in env OVERUB_SESSION_STRING.")
+
+
+def main() -> None:
+    asyncio.run(generate())
+
+
+if __name__ == "__main__":
+    main()