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/services/timesheet.service.js

@@ -68,7 +68,7 @@ const safeUnlink = async (filePath) => {
     await fs.unlink(filePath);
   } catch (error) {
     // Keep server responsive even if cleanup fails
-    console.error('Failed to delete file:', error);
+    console.error('Nepodarilo sa zmazať súbor:', error);
   }
 };