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

app/projects/[projectId]/meetings/page.tsx

@@ -0,0 +1,72 @@
+import { redirect } from 'next/navigation';
+import { getCurrentUser, toPublicUser } from '@/lib/auth/getCurrentUser';
+import { createMeetingService, createProjectService } from '@/lib/api/services';
+import { Header } from '@/components/layout/Header';
+import { ProjectNav } from '@/components/layout/ProjectNav';
+import { MeetingForm } from '@/components/meetings/MeetingForm';
+import { ForbiddenError, NotFoundError } from '@/lib/errors';
+
+export const dynamic = 'force-dynamic';
+
+export default async function MeetingsPage({
+  params,
+}: {
+  params: Promise<{ projectId: string }>;
+}) {
+  const user = await getCurrentUser();
+  if (!user) redirect('/login');
+  const { projectId } = await params;
+
+  const projectService = createProjectService();
+  let project: Awaited<ReturnType<typeof projectService.getProject>>;
+  try {
+    project = projectService.getProject(user.id, Number(projectId));
+  } catch (error) {
+    if (error instanceof ForbiddenError || error instanceof NotFoundError) {
+      redirect('/dashboard');
+    }
+    throw error;
+  }
+
+  const meetingService = createMeetingService();
+  const meetings = meetingService.getMeetings(user.id, project.id);
+  const members = projectService.getMembers(user.id, project.id).map((m) => ({
+    userId: m.userId,
+    name: m.user.name,
+  }));
+
+  return (
+    <div className="min-h-screen bg-gray-50">
+      <Header user={toPublicUser(user)} />
+      <ProjectNav projectId={project.id} active="meetings" />
+      <main className="mx-auto max-w-3xl space-y-6 p-6">
+        <h1 className="text-2xl font-bold">ミーティング</h1>
+        <MeetingForm projectId={project.id} members={members} />
+        <section className="space-y-3">
+          {meetings.length === 0 ? (
+            <p className="text-sm text-gray-400">ミーティングはありません。</p>
+          ) : (
+            meetings.map((m) => (
+              <div
+                key={m.id}
+                className="rounded-lg border bg-white p-4 shadow-sm"
+                data-testid={`meeting-${m.id}`}
+              >
+                <h3 className="font-semibold text-gray-800">{m.title}</h3>
+                <p className="text-xs text-gray-500">
+                  {m.startAt} 〜 {m.endAt}
+                </p>
+                {m.location && (
+                  <p className="text-xs text-gray-500">場所: {m.location}</p>
+                )}
+                {m.minutesMd && (
+                  <p className="mt-2 text-sm text-gray-600">議事録あり</p>
+                )}
+              </div>
+            ))
+          )}
+        </section>
+      </main>
+    </div>
+  );
+}