[US-030] Total profile visits over time (analytics)

[leimo2011]

Epic: EP-07 — Store Admin Analytics Dashboard \nPriority: Must Have (M) \nStory Points: 5 \nSprint: Sprint 3\n\n### User Story\nAs a store admin, I want to see total profile visits over time so I know my reach.\n\n### Acceptance Criteria\n- [ ] Line chart showing daily/weekly profile views\n- [ ] Date range selector (7d, 30d, 90d based on plan)\n- [ ] Total visits count shown prominently\n- [ ] Free tier limited to last 7 days\n- [ ] Pro/Enterprise shows up to 90 days / full history\n\n### Technical Notes\n- Analytics events aggregated by Celery task nightly\n- GET /api/analytics/stores/{id}/visits/?range=30d\n- analytics_events table: event_type=VIEW