Fix /myshifts route being incorrectly matched as shift ID

[AngeloZois]

Summary

Fixes an issue where the Employer Dashboard was unable to load shifts because the /api/v1/shifts/myshifts endpoint was being incorrectly handled by the dynamic /:id route.

Problem

When the Employer Dashboard requested /api/v1/shifts/myshifts, Express matched myshifts as the :id parameter. The backend then attempted to validate myshifts as a MongoDB ObjectId and returned a 400 Invalid id response.

Fix

Moved the /myshifts route above the /:id route in shift.routes.js so the specific route is matched before the dynamic ID route.

Testing

• Rebuilt the backend Docker container.
• Tested the Employer login and dashboard locally.
• Confirmed /myshifts now loads successfully.
• Confirmed the Employer Dashboard displays the seeded shifts instead of the Invalid id error.