feat: a day of the activity map opens what happened, ticket by ticket

On the project dashboard, a day with activity can be picked on the map:
a side panel lists that day's moves grouped by ticket (each key opens
it), with the time of each, and the project's own (sprints, releases,
members) apart.

The activity feed takes an `after` date (GraphQL, REST), so with
`before` it reads a window such as a day; the MCP's
get_project_activity takes a `day`.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

apps/api/e2e/tracker.e2e-spec.ts

@@ -1425,6 +1425,26 @@ describe('task-stream (e2e)', () => {
     expect(insights.body['journey']).toMatchObject({ samples: 0, steps: [] });
     expect(insights.body['proposals']).toBeNull();
 
+    // A day of it: only what happened between after and before.
+    const tomorrow = new Date(Date.parse(`${today}T00:00:00Z`) + 86_400_000);
+    const ofToday = await rest(
+      'token-ana',
+      'GET',
+      `/projects/${key}/activity?after=${today}T00:00:00.000Z&before=${tomorrow.toISOString()}&limit=200`,
+    );
+    expect(ofToday.body.length).toBeGreaterThan(0);
+    expect(
+      ofToday.body.every((a: { occurredAt: string }) =>
+        a.occurredAt.startsWith(today),
+      ),
+    ).toBe(true);
+    const ofYesterday = await rest(
+      'token-ana',
+      'GET',
+      `/projects/${key}/activity?after=2020-01-01T00:00:00.000Z&before=2020-01-02T00:00:00.000Z`,
+    );
+    expect(ofYesterday.body).toEqual([]);
+
     // What changed since a moment, and what the backlog lacks.
     const since = new Date(Date.now() - 60_000).toISOString();
     const later = await rest(