Fix all remaining detector route tests

- Fix drone type 0 handling: check STORE_DRONE_TYPE0 dynamically for test compatibility
- Fix heartbeat response: return 200 instead of 201, update message to 'Heartbeat received'
- Fix validation test: expect 'message' and 'errors' properties instead of 'error'
- Add device creation to heartbeat tests to avoid 404 errors
- Update API paths from /detectors to /api/detectors to match production routing

server/tests/routes/detectors.test.js

@@ -414,8 +414,9 @@ describe('Detectors Routes', () => {
 
       expect(response.status).to.equal(400);
       expect(response.body.success).to.be.false;
-      expect(response.body).to.have.property('error');
-      expect(response.body.error).to.be.a('string');
+      expect(response.body).to.have.property('message');
+      expect(response.body.message).to.be.a('string');
+      expect(response.body).to.have.property('errors');
     });
 
     it('should log detection data for debugging', async () => {