feat(agents): sort AgentRun list via query state

[gregkonush]

Summary

• Added AgentRun-specific sortable table headers for name, status, agent, implementation, namespace, and age.
• Made /primitives/agent-run sort state derive from validated URL query params, with safe aliases/defaults and URL-updating header interactions.
• Preserved query-backed filters such as namespace, phase/status, runtime, label selector, limit, page, and search state while changing sort.
• Added focused unit coverage for query parsing, sort serialization, deterministic sorting, and filter preservation.

Related Issues

None

Testing

• PASS: bun run --cwd services/agents tsc
• PASS: bun run --cwd services/agents lint
• PASS: bun run --cwd services/agents test
• PASS: Browser QA with Playwright screenshot at /tmp/agentrun-sort-rebased.png for http://127.0.0.1:3000/primitives/agent-run?sort=createdAt&direction=desc&status=Running; verified dark shell, breadcrumbs/sidebar, status filter, sortable headers, active age descending indicator, and loading table layout.
• PASS: Browser QA with Playwright click automation; clicked Sort AgentRuns by Name and verified URL changed to /primitives/agent-run?sort=name&direction=asc&status=Running, preserving the status filter.

Screenshots (if applicable)

Local visual QA screenshot captured at /tmp/agentrun-sort-rebased.png; not attached to this PR.

Breaking Changes

None

Checklist

• Testing section documents the exact validation performed.
• Screenshots and Breaking Changes sections are handled appropriately.
• Documentation, release notes, and follow-ups are updated or tracked; no documentation changes were required for this UI-only enhancement.