feat(services): paginate top agents

[ZaaK0913-coder]

Summary

• Add server-driven paging to the service top-agents page using page and limit query params.
• Show the shared Spinner while loading, EmptyState for no agents, and Pagination for multi-page results.
• Link ranked agent rows to encoded /agents/:agent routes while preserving the existing error path.
• Document the top-agents paging behavior in README.

Closes #64

Validation

• npx.cmd jest --runTestsByPath "src/app/services/[serviceId]/agents/page.test.tsx" --runInBand
• npx.cmd jest --runTestsByPath "src/app/services/[serviceId]/agents/page.test.tsx" --coverage --collectCoverageFrom="src/app/services/[serviceId]/agents/page.tsx" --coverageReporters=text --coverageThreshold "{}" --runInBand
• npx.cmd eslint "src/app/services/[serviceId]/agents/page.tsx" "src/app/services/[serviceId]/agents/page.test.tsx"
• npx.cmd prettier --check "src/app/services/[serviceId]/agents/page.tsx" "src/app/services/[serviceId]/agents/page.test.tsx"

Typecheck note

• npm.cmd run typecheck was attempted and is currently blocked by pre-existing main-branch errors outside this change:
  • src/app/agents/[agent]/page.tsx: missing Breadcrumb and formatRequests
  • src/app/docs/page.tsx: missing safeHref