Complete editable fields whitelists for all remaining AE objects

- Created .editable_fields.ts files for Journals, Events, and Sponsorships modules
- Standardized the whitelist pattern across the entire codebase
- Updated TODO.md and GEMINI.md with recent accomplishments and learnings

src/lib/ae_events/ae_events__event_file.editable_fields.ts

@@ -0,0 +1,12 @@
+export const editable_fields__event_file = [
+    'filename',
+    'extension',
+    'open_in_os',
+    'file_purpose',
+    'enable',
+    'hide',
+    'priority',
+    'sort',
+    'group',
+    'notes'
+];