refactor: Standardize data processing and update to Svelte 5 runes

This commit introduces a major refactoring of the data processing logic across multiple modules (events, archives, posts, sponsorships) to use a standardized pattern with . This improves consistency and maintainability.

Key changes:
- Replaced module-specific data processing with a generic helper.
- Removed deprecated  functions.
- Updated Svelte components to leverage the new Svelte 5 runes, simplifying state management.
- Fixed linting errors and updated test configurations.
- Added .

src/lib/ae_posts/db_posts.ts

@@ -1,6 +1,6 @@
 import Dexie, { type Table } from 'dexie';
 
-import type { key_val } from '../ae_stores';
+import type { key_val } from '$lib/stores/ae_stores';
 
 // li = list
 // kv = key value list