fix: Modal API authentication working with SDK

- Discovered Modal requires SDK, not raw HTTP
- Token ID and Secret work with modal.Client.from_credentials()
- Raw HTTP calls don't work (need SDK)
- Updated documentation with correct usage
- Modal SDK authentication verified and working

Next: Integrate Modal SDK for scraping assistance when direct methods fail

agents/junior-ae/state/jae-v4-state.json

@@ -1,5 +1,5 @@
 {
-  "last_check": "2026-04-10T13:10:34.858296",
+  "last_check": "2026-04-10T19:13:06.810664",
   "processed": 0,
   "upgraded": 0,
   "processed_ids": [