feat: Replace Meetings with Calendar - events with types and assigned users

- Rename meetings table to events with type field (meeting/event)
- Add eventUsers junction table for user assignments
- Members see only events they're assigned to
- Calendar endpoint returns events + todos for month
- Add migration SQL for database changes

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

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

src/validators/crm.validators.js

@@ -171,3 +171,22 @@ export const updateTimeEntrySchema = z.object({
   companyId: optionalUuid('Neplatný formát company ID'),
   description: optionalDescription,
 });
+
+// Event validators
+export const createEventSchema = z.object({
+  title: z.string().min(1, 'Názov je povinný'),
+  description: z.string().optional(),
+  type: z.enum(['meeting', 'event']).default('meeting'),
+  start: z.string().min(1, 'Začiatok je povinný'),
+  end: z.string().min(1, 'Koniec je povinný'),
+  assignedUserIds: z.array(z.string().uuid('Neplatný formát user ID')).optional(),
+});
+
+export const updateEventSchema = z.object({
+  title: z.string().min(1).optional(),
+  description: z.string().optional(),
+  type: z.enum(['meeting', 'event']).optional(),
+  start: z.string().optional(),
+  end: z.string().optional(),
+  assignedUserIds: z.array(z.string().uuid('Neplatný formát user ID')).optional(),
+});