Restore Event Session search stability and advance platform-wide string ID standardization

- Restored Event Session search by standardizing on 'event_id' for Dexie queries and implementing dual-layer filtering (local + API guard) to prevent broad results from clobbering filtered views.
- Advanced String-Only ID Standardization (Phase 2) by updating generic object processors across all event library modules to support both base IDs and legacy '_random' variants.
- Refactored Event Presenter and Presentation components to support standardized '_id_li' props while maintaining backward compatibility.
- Standardized common helper identifiers to snake_case (e.g., 'prevent_default') in the Events module.
- Verified Staff and Poster email notification logic in the Bulletin Board module.
- Updated .gitignore and cleaned up test artifacts.

src/lib/ae_events/ae_events__event_presentation.ts

@@ -313,7 +313,9 @@ async function _process_generic_props<T extends Record<string, any>>({ obj_li, o
             }
         }
         const randomIdKey = `${obj_type}_id_random`;
+        const baseIdKey = `${obj_type}_id`;
         if (processed_obj[randomIdKey]) (processed_obj as any).id = processed_obj[randomIdKey];
+        else if (processed_obj[baseIdKey]) (processed_obj as any).id = processed_obj[baseIdKey];
         const group = processed_obj.group ?? '0';
         const priority = processed_obj.priority ? 1 : 0;
         const sort = processed_obj.sort ?? '0';