fix: add :submission to audit log event types

Bug found during testing: AuditLog.log(:submission, ...) was failing
because :submission wasn't in the @event_types list.

This fix allows the submitter to log submission events properly.

Test results:
- ✅ Version check working
- ✅ Help output working
- ✅ GitHub dry-run working
- ✅ Bugzilla integration ready (needs credentials)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Jonathan D.A. Jewell

elixir-mcp/_build/dev/lib/feedback_a_tron/.mix/compile.elixir

@@ -31,6 +31,7 @@ defmodule FeedbackATron.AuditLog do
 
   # Event types
   @event_types [
+    :submission,
     :submission_attempt,
     :submission_success,
     :submission_failure,