feat: port remaining cohort scripts and make reusable

- Port 19 cohort scripts from /home/naomi/docs/cohort/
- Replace all hardcoded tokens and dotenv usage with os.environ
- Add pandas==3.0.1 dependency
- Add E501 to ruff ignore list for Discord message string content
- Make remove_resigned_members.py reusable (empty RESIGNED_IDS constant)
- Make update_roster_messages.py reusable (iterates all teams from JSON)
- Exclude 12 one-off/event-specific scripts as non-reusable

python/cohort/fetch_roster.py

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+"""Fetch pinned messages from Ivory Orchid channel to find the roster."""
+
+import asyncio
+import json
+import os
+
+import aiohttp
+
+DISCORD_BOT_TOKEN = os.environ["DISCORD_BOT_TOKEN"]
+CHANNEL_ID = "1464316770889240730"
+
+
+async def main() -> None:
+    """Fetch and print pinned messages from the Ivory Orchid channel."""
+    headers = {
+        "Authorization": f"Bot {DISCORD_BOT_TOKEN}",
+        "Content-Type": "application/json",
+    }
+
+    async with (
+        aiohttp.ClientSession() as session,
+        session.get(
+            f"https://discord.com/api/v10/channels/{CHANNEL_ID}/pins",
+            headers=headers,
+        ) as response,
+    ):
+        pins = await response.json()
+        print(json.dumps(pins, indent=2))
+
+
+if __name__ == "__main__":
+    asyncio.run(main())