Refactor: Split jmap.service.js into modules and update Slovak translations

- Split 753-line jmap.service.js into modular structure:
  - jmap/config.js: JMAP configuration functions
  - jmap/client.js: Base JMAP requests (jmapRequest, getMailboxes, getIdentities)
  - jmap/discovery.js: Contact discovery from JMAP
  - jmap/search.js: Email search functionality
  - jmap/sync.js: Email synchronization
  - jmap/operations.js: Email operations (markAsRead, sendEmail)
  - jmap/index.js: Re-exports for backward compatibility

- Update all imports across codebase to use new module structure

- Translate remaining English error/log messages to Slovak:
  - email.service.js: JMAP validation messages
  - admin.service.js: Email account creation error
  - audit.service.js: Audit event logging error
  - timesheet.service.js: File deletion error
  - database.js: Database error message

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

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

src/config/database.js

@@ -17,7 +17,7 @@ const pool = new Pool({
 
 // Note: Connection logging handled in index.js to avoid circular dependencies
 pool.on('error', (err) => {
-  console.error('Unexpected database error:', err);
+  console.error('Neočakávaná chyba databázy:', err);
   process.exit(-1);
 });