feat: implement work items v1

[vsevolod]

Summary

• add work item persistence, service layer, GitHub/Jira sync, Slack review actions, dashboard APIs, kanban interactions, and delivery automation foundations
• include Kubernetes runtime changes that were pulled into this branch; that scope should be reviewed separately in Feat/kubernetes runtime #10
• close dashboard pipeline test servers during teardown and verify the full Task 10 suite

Blockers

• blocked by Feat/kubernetes runtime #10: Feat/kubernetes runtime Feat/kubernetes runtime #10

Test Plan

• docker compose up -d postgres
• docker compose run --rm -e DATABASE_URL_TEST=postgres://gooseherd:gooseherd@postgres:5432/gooseherd_test -v "$PWD:/app" --entrypoint sh gooseherd -lc 'node --test --import tsx tests/work-item-store.test.ts tests/work-item-policies.test.ts tests/work-item-service.test.ts tests/work-item-github-sync.test.ts tests/dashboard-work-items.test.ts'
• docker compose run --rm -e DATABASE_URL_TEST=postgres://gooseherd:gooseherd@postgres:5432/gooseherd_test -v "$PWD:/app" --entrypoint sh gooseherd -lc 'node --test --import tsx tests/config.test.ts tests/dashboard-pipelines.test.ts tests/slack-thread.test.ts tests/observer.test.ts'
• docker compose run --rm -e DATABASE_URL_TEST=postgres://gooseherd:gooseherd@postgres:5432/gooseherd_test -v "$PWD:/app" --entrypoint sh gooseherd -lc 'npm run check'