Worktree merge and delete context actions

[DingDingChae]

Current status

Implementation is complete on c5222a3a988b779686053a498defb2a120d246da and pushed on codex/worktree-context-menu-actions. Integration into main is the remaining step.

What changed

• Eligible linked worktrees now expose Merge… in their right-click menu.
• The action opens the existing reviewed merge flow with the exact local branch selected.
• Delete… remains separate and keeps main-worktree, locked-worktree, and non-force protections.
• Screenshot documentation now declares and generates pages for both new built-interface captures.

Verification

Check	Result
Focused menu and screenshot documentation	45 passed
Capture-plan contract	60 passed
TypeScript	Passed
Changed-file ESLint	Passed
Production build	Passed in 337.36 seconds
Built-interface interaction	Merge menu and merge preview verified at 960×660

Tracking issue: #219.

香港粵語

linked worktree 右鍵選單而家有條件式 Merge…，會開返原本有預覽嗰套流程，仲會揀啱 branch；Delete… 仍然分開處理，安全限制冇少。程式、測試同真實離屏畫面都驗過，下一步係整合入 main。

[DingDingChae]

🔀 Main integration milestone

main now points to f10f1e8097a85fe220013635fb2a74433a27f465, and a direct remote ref read returned the same SHA. The feature commit c5222a3a98 is its ancestor.

• ✅ CI Linux: 33565664674
• ✅ Cheap LFS cloud compression: 33565664792
• 🏃 CI Windows: 33565664741

The task remains open until the Windows run is terminal.

香港粵語：main 同遠端 ref 已經對到同一個 f10f1e8097；兩個 workflow 完成，Windows 仲跑緊，所以繼續等真 verdict，唔估。