Feat/UI queue concurrency status 323

[ivasuy]

Summary

Expose per-agent queue concurrency in the UI using the new /api/ui/v1/queue/status response shape.
This adds per-agent running/max/available visibility, capacity highlighting, and total running status on the dashboard/header so users can immediately detect saturation.

Type of change

• Bug fix
• New feature
• Refactor / cleanup
• Docs only
• Tests only
• CI / tooling
• Breaking change

Test plan

• npm --prefix control-plane/web/client test -- src/test/hooks/useSystemHealth.test.tsx src/test/components/HealthStrip.test.tsx src/test/pages/NewDashboardPage.test.tsx src/pages/NewDashboardPage.test.tsx
• Manual validation:
  • Start server with AGENTFIELD_MAX_CONCURRENT_PER_AGENT=3
  • Run test-slow agent
  • Fire 5 parallel requests to test-slow.slow_task
  • Confirm 3x 200 and 2x 429
  • Confirm dashboard shows queue capacity warning + per-agent slot usage
• ./scripts/coverage-summary.sh && ./scripts/patch-coverage-gate.sh

Test coverage

• I ran tests for the surface(s) I changed locally.
• New code paths are covered by tests in this PR (no bare additions).
• If I removed code, I updated coverage-baseline.json in this PR only if the removal caused a legitimate regression and I called it out in the summary above.
• The coverage gate check is green in CI before requesting review.

Checklist

• I have read CONTRIBUTING.md (if present) and docs/DEVELOPMENT.md.
• Commits are signed and follow conventional-commits style.
• I have linked any related issues (Fixes feat(tests): add unit tests for vector memory handler functionality #123 / Closes test: add tests for TypeScript SDK utils (pattern, schema, httpAgents) #456).

Related issues / PRs

Closes #323
Refs #316
Refs #319

Screenshots

• Dashboard: Queue concurrency card visible with at-capacity state

• Header: Queue status tooltip/popover showing per-agent running/max/available

[github-actions]

Performance

SDK	Memory	Δ	Latency	Δ	Tests	Status
Python	9.4 KB	+4%	0.32 µs	-9%	✓	✓

✓ No regressions detected

[github-actions]

📊 Coverage gate

Thresholds from .coverage-gate.toml: per-surface ≥ 86%, aggregate ≥ 88%, max per-surface regression ≤ 1.0 pp, max aggregate regression ≤ 0.50 pp.

Surface	Current	Baseline	Δ
control-plane	87.40%	87.30%	↑ +0.10 pp	🟡
sdk-go	91.90%	90.70%	↑ +1.20 pp	🟢
sdk-python	93.66%	93.63%	↑ +0.03 pp	🟢
sdk-typescript	92.68%	92.56%	↑ +0.12 pp	🟢
web-ui	89.89%	90.01%	↓ -0.12 pp	🟡
aggregate	88.97%	89.01%	↓ -0.04 pp	🟡

✅ Gate passed

No surface regressed past the allowed threshold and the aggregate stayed above the floor.

[github-actions]

📐 Patch coverage gate

Threshold: 80% on lines this PR touches vs origin/main (from .coverage-gate.toml:thresholds.min_patch).

Surface	Touched lines	Patch coverage	Status
control-plane	0	—	➖ no changes
sdk-go	0	—	➖ no changes
sdk-python	0	—	➖ no changes
sdk-typescript	0	—	➖ no changes
web-ui	175	100.00%	✅

✅ Patch gate passed

Every surface whose lines were touched by this PR has patch coverage at or above the threshold.