Update docs site concepts and references

[version-1]

Update Docs Site Concepts and References

Summary

Refresh the docs site for the current Tasq workflow: command-based onboarding, agent-driven task flow, Codex recovery, Concepts pages, and Reference pages.

主な変更点:

• Added an Agent Tutorial after QuickStart and linked QuickStart to it.
• Expanded Setup Guide with a concrete WORKFLOW.md setup example.
• Updated Concepts and Reference docs for task dependencies, queue/watch behavior, orchestrator runtime APIs, and current status enums.
• Added shell code highlighting and spacing refinements for docs-site code blocks.

チケットへのリンク

ここはまだない

やったこと

• Added English and Japanese Agent Tutorial pages.
• Updated English and Japanese QuickStart, Setup Guide, Overview, Concepts, and Reference pages.
• Added Codex blocked-session recovery links to Recover a Blocked Session.
• Enabled Prism bash language highlighting and refined sh code block CSS.

動作確認

• npm run build from docs/site
• Confirmed branch is based on latest origin/main
• Confirmed working tree is clean before PR creation

レビュー & 動作確認 チェックリスト

• Getting Started flow - QuickStart leads to the new Agent Tutorial and Setup Guide without conflicting guidance.
• Reference accuracy - CLI/API/schema/config updates match current implementation contracts.
• Japanese docs parity - Japanese pages stay synchronized with the English source pages.

推奨テスト計画:

1. Open the docs site locally with npm run serve after build.
2. Check QuickStart, Agent Tutorial, Setup Guide, Concepts Overview, and Reference pages in both English and Japanese.
3. Verify shell code blocks render with highlighting and spacing.

その他気になることや相談ごと

なし

Notes
Requested by: user