feat(agents): format request counts on the agent detail page

[GBOYEE]

Summary

Routes the lifetime total and per-service request counts on the agent detail page through formatRequests for consistent locale thousands grouping.

Closes #155

Changes

• Import formatRequests from @/lib/format in src/app/agents/[agent]/page.tsx
• Wrap lifetime total with formatRequests(total)
• Wrap each per-service total with `formatRequests(s.total))

Tests

• Added 4 new test cases covering: large total grouping, per-service grouping, zero total, and absent optional total
• All 7 tests in the page test suite pass
• npm run lint and npm run typecheck clean on changed files

Test output

PASS src/app/agents/[agent]/page.test.tsx
  AgentDetailPage
    ✓ renders the Breadcrumb trail with an Agents link and a current-page item
    ✓ handles long agent identifiers correctly in breadcrumb
    ✓ handles special characters in the agent identifier
    ✓ formats a large lifetime total with thousands separators
    ✓ formats per-service totals with thousands separators
    ✓ renders zero total without grouping
    ✓ does not render lifetime total when the optional total fetch fails

Test Suites: 1 passed, 1 total
Tests:       7 passed, 7 total

[mikewheeleer]

lgtm — merging this 🙌