feat(m12): meetings + schedule conflict detection, tests, e2e

- MeetingRepository (CRUD, soft-delete, members, findMeetingsByUserInRange
  overlap) + CalendarRepository.findByCreatorInRange + TodoRepository.
  findHighPriorityByAssignee
- MeetingService (createMeeting tx+members, meeting_invited notify,
  meeting_created activity, SSE meeting.created; updateMeeting/updateMinutes/
  deleteMeeting; checkScheduleConflicts = other meetings overlap + calendar
  events overlap + high-priority todos due +-3d, time-overlap logic,
  excludeMeetingId; conflicts are warnings)
- APIs: meetings list/create/edit + /check conflict check
- Screens: meetings page + MeetingForm(member checkboxes, conflict display)
  + ConflictWarning, ProjectNav link
- Unit tests (MeetingRepository, MeetingService incl. conflict algorithm)
  + e2e meetings

lib/api/services.ts

@@ -21,6 +21,8 @@ import { FileRepository } from '@/repositories/FileRepository';
 import { ScheduleService } from '@/services/ScheduleService';
 import { CalendarRepository } from '@/repositories/CalendarRepository';
 import { MilestoneRepository } from '@/repositories/MilestoneRepository';
+import { MeetingService } from '@/services/MeetingService';
+import { MeetingRepository } from '@/repositories/MeetingRepository';
 
 /**
  * Route Handler用に各Repository/Serviceを構築するファクトリ。
@@ -110,6 +112,20 @@ export function createScheduleService(): ScheduleService {
   );
 }
 
+export function createMeetingService(): MeetingService {
+  const db = getDb();
+  return new MeetingService(
+    new MeetingRepository(db),
+    new CalendarRepository(db),
+    new TodoRepository(db),
+    new ProjectMemberRepository(db),
+    new NotificationService(new NotificationRepository(db)),
+    new ActivityLogService(new ActivityLogRepository(db)),
+    getSseHub(),
+    db
+  );
+}
+
 export function createUserRepository(): UserRepository {
   return new UserRepository(getDb());
 }