Add Time Tracking backend API

Implementovaný kompletný backend pre time tracking:
- Nová tabuľka time_entries s foreign keys na users, projects, todos, companies
- Service layer s business logikou pre CRUD operácie
- Controller pre všetky endpointy
- Validačné schémy pomocou Zod
- Routes s autentifikáciou a validáciou
- Endpointy:
  * POST /api/time-tracking/start - Spustenie timeru
  * POST /api/time-tracking/:id/stop - Zastavenie timeru
  * GET /api/time-tracking/running - Získanie bežiaceho záznamu
  * GET /api/time-tracking/month/:year/:month - Mesačné záznamy
  * GET /api/time-tracking/stats/monthly/:year/:month - Mesačné štatistiky
  * PATCH /api/time-tracking/:id - Aktualizácia záznamu
  * DELETE /api/time-tracking/:id - Zmazanie záznamu
- Podpora pre isEdited flag pri editácii
- Kalkulácia duration v minútach

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

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

src/routes/time-tracking.routes.js

@@ -0,0 +1,91 @@
+import express from 'express';
+import * as timeTrackingController from '../controllers/time-tracking.controller.js';
+import { authenticate } from '../middlewares/auth/authMiddleware.js';
+import { validateBody, validateParams } from '../middlewares/security/validateInput.js';
+import {
+  startTimeEntrySchema,
+  stopTimeEntrySchema,
+  updateTimeEntrySchema,
+} from '../validators/crm.validators.js';
+import { z } from 'zod';
+
+const router = express.Router();
+
+// All time tracking routes require authentication
+router.use(authenticate);
+
+/**
+ * Time Tracking management
+ */
+
+// Start new time entry
+router.post('/start', validateBody(startTimeEntrySchema), timeTrackingController.startTimeEntry);
+
+// Stop running time entry
+router.post(
+  '/:entryId/stop',
+  validateParams(z.object({ entryId: z.string().uuid() })),
+  validateBody(stopTimeEntrySchema),
+  timeTrackingController.stopTimeEntry
+);
+
+// Get running time entry
+router.get('/running', timeTrackingController.getRunningTimeEntry);
+
+// Get all time entries with filters
+router.get('/', timeTrackingController.getAllTimeEntries);
+
+// Get monthly time entries
+router.get(
+  '/month/:year/:month',
+  validateParams(
+    z.object({
+      year: z.string().regex(/^\d{4}$/, 'Rok musí byť 4-ciferné číslo'),
+      month: z.string().regex(/^(0?[1-9]|1[0-2])$/, 'Mesiac musí byť číslo 1-12'),
+    })
+  ),
+  timeTrackingController.getMonthlyTimeEntries
+);
+
+// Get monthly statistics
+router.get(
+  '/stats/monthly/:year/:month',
+  validateParams(
+    z.object({
+      year: z.string().regex(/^\d{4}$/, 'Rok musí byť 4-ciferné číslo'),
+      month: z.string().regex(/^(0?[1-9]|1[0-2])$/, 'Mesiac musí byť číslo 1-12'),
+    })
+  ),
+  timeTrackingController.getMonthlyStats
+);
+
+// Get time entry by ID
+router.get(
+  '/:entryId',
+  validateParams(z.object({ entryId: z.string().uuid() })),
+  timeTrackingController.getTimeEntryById
+);
+
+// Get time entry with relations
+router.get(
+  '/:entryId/details',
+  validateParams(z.object({ entryId: z.string().uuid() })),
+  timeTrackingController.getTimeEntryWithRelations
+);
+
+// Update time entry
+router.patch(
+  '/:entryId',
+  validateParams(z.object({ entryId: z.string().uuid() })),
+  validateBody(updateTimeEntrySchema),
+  timeTrackingController.updateTimeEntry
+);
+
+// Delete time entry
+router.delete(
+  '/:entryId',
+  validateParams(z.object({ entryId: z.string().uuid() })),
+  timeTrackingController.deleteTimeEntry
+);
+
+export default router;