feat(hunt): track walking distance via GPS, show live locations on map

Add foreground-only GPS distance tracking for hunts

tests/integration/submit.itest.ts

@@ -192,4 +192,52 @@ describe('submit answer (POST /api/quest/[questId]/submit)', () => {
     );
     expect(res.status).toBe(418);
   });
+
+  it('persists lat/lon when submitted with the answer', async () => {
+    const { quest, team } = await seedPlayground('owner@test.dev');
+
+    const client = newClient();
+    await client.login('owner@test.dev', TEST_PASSWORD);
+    const res = await client.post(
+      `/api/quest/${quest.id}/submit`,
+      form({ answer: 'here', lat: '52.520008', lon: '13.404954' })
+    );
+    expect(res.status).toBe(200);
+
+    const answer = await prisma.questAnswer.findFirstOrThrow({
+      where: { teamId: team.id, questId: quest.id }
+    });
+    expect(Number(answer.lat)).toBeCloseTo(52.520008, 5);
+    expect(Number(answer.lon)).toBeCloseTo(13.404954, 5);
+  });
+
+  it('leaves lat/lon null when not submitted', async () => {
+    const { quest, team } = await seedPlayground('owner@test.dev');
+
+    const client = newClient();
+    await client.login('owner@test.dev', TEST_PASSWORD);
+    await client.post(
+      `/api/quest/${quest.id}/submit`,
+      form({ answer: 'no location' })
+    );
+
+    const answer = await prisma.questAnswer.findFirstOrThrow({
+      where: { teamId: team.id, questId: quest.id }
+    });
+    expect(answer.lat).toBeNull();
+    expect(answer.lon).toBeNull();
+  });
+
+  it('never creates a TrackPoint from a submission', async () => {
+    const { quest } = await seedPlayground('owner@test.dev');
+
+    const client = newClient();
+    await client.login('owner@test.dev', TEST_PASSWORD);
+    await client.post(
+      `/api/quest/${quest.id}/submit`,
+      form({ answer: 'here', lat: '52.520008', lon: '13.404954' })
+    );
+
+    expect(await prisma.trackPoint.count()).toBe(0);
+  });
 });