fix: prevent double date formatting in email templates

- Remove pre-formatting of dates before passing to email processor
- Let email processor handle all date formatting based on recipient language
- Fix Invalid Date errors by passing raw date values instead of formatted strings
- Remove unused formatDate imports and variables

🤖 Generated with [Claude Code](https://claude.ai/code)

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

backend/src/database/db.js

@@ -59,9 +59,9 @@ async function initializeDatabase() {
           )
         `);
         
-        await db.raw(`INSERT INTO events_new SELECT * FROM events`);
-        await db.raw(`DROP TABLE events`);
-        await db.raw(`ALTER TABLE events_new RENAME TO events`);
+        await db.raw('INSERT INTO events_new SELECT * FROM events');
+        await db.raw('DROP TABLE events');
+        await db.raw('ALTER TABLE events_new RENAME TO events');
       } catch (error) {
         // If the migration fails, it might already have been applied
         console.log('Color theme migration may have already been applied');