feat: Add health check endpoints (#699) (#796)

* feat: Add priority and component fields to issue templates (#704)

- Added Priority field (P1-P4) to all issue templates
- Added Component field (Backend, Frontend, AI Engine, Database, etc.) to all templates
- Updated bug_report.md, feature_request.md, config.md, documentation.md, and question.md

This enhances issue #704 with structured task submission with custom fields.

Co-authored-by: openhands <openhands@all-hands.dev>

* Update CODEOWNERS with anchapin as owner

- Replace @alex with @anchapin as the code owner for all components
- Maintain code ownership for frontend/, backend/, ai-engine/
- Keep .github/ ownership under anchapin
- Requires 1 review from code owners before merging

Co-authored-by: openhands <openhands@all-hands.dev>

* docs: Add health check endpoints documentation (Issue #699)

- Add comprehensive health check documentation in docs/health-checks.md
- Document /health, /health/liveness, and /health/readiness endpoints
- Include Kubernetes probe configuration examples
- Update documentation index

Co-authored-by: openhands <openhands@all-hands.dev>

* feat: Add health check endpoints with Redis dependency checks (Issue #699)

- Add /health/readiness and /health/liveness endpoints to AI engine
- Add DependencyHealth model for detailed dependency status
- Add Redis health check with latency measurement
- Update README with AI engine health endpoint documentation

Co-authored-by: openhands <openhands@all-hands.dev>

* fix: Correct opentelemetry-exporter-jaeger package name

The package 'opentelemetry-exporter-jaeger-thrift' doesn't exist.
Changed to 'opentelemetry-exporter-jaeger==1.21.0' which is the
latest version compatible with Python 3.11.

* fix: Fix WebSocket URL test expectation in ConversionProgress.test.tsx

The test expected an absolute WebSocket URL (ws://localhost:8080/...) but
the component uses relative URLs when API_BASE_URL is not set in tests.

Fixes #774 - Updates test expectation to match actual behavior:
- Changed expected URL from 'ws://localhost:8080/ws/v1/convert/test-job-123/progress'
  to '/ws/v1/convert/test-job-123/progress'
- Added MockWebSocket.instances clearing for test isolation

Co-authored-by: openhands <openhands@all-hands.dev>

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Co-authored-by: openhands <openhands@all-hands.dev>
Co-authored-by: Amp <amp@ampcode.com>

Author: 3 people