Fix fetch logs: broken new-patch detection, bad format, stale duplicates

- New patch detection was comparing vendor patches against themselves
  (always finding 0 new). Now compares against previous patches.json.
- Log format changed to "[STATUS] vendor - message" to match the
  display regex. Old format "[INFO] No new patches for X" was parsed
  with "No" as the vendor name.
- Cleared 13 identical stale log entries, capped history at 50.

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

Author: Toreburn