恢復分頁 TUI 並修正鍵盤選取捲動

[0xroylee]

Task

恢復分頁 TUI 並修正鍵盤選取捲動
Related issue: #104

Validation

• bun run check passed: lint, typecheck, and 356 tests.
• Required four-file test command passed: 40 tests covering navigation, details, resize, refresh recovery, terminal restoration, and 40/80/120-column selection and scrolled mouse targets.
• bun test test/cli/github-commands.test.ts passed: 4 tests.

Risks

• Final-commit independent Review remains required.

Limitations

• Physical 80×24 and 40×24 visual inspection was not completed; the attempted PTY CLI smoke check timed out. Terminal I/O fixtures passed.

Acceptance checklist

Automated Review evidence for head 8469a6137c4ff76843697f26a1dc7c7dae345a12; human acceptance is separate.

• tui 預設顯示 Welcome；task board 直接顯示 Tasks，兩者均不啟動執行。
  Status: passed
  Evidence:
  CLI fixtures verified Welcome and direct Tasks entry with zero scheduler calls. Actual tui CLI PTY launches exited successfully at 40 and 80 columns.
• 沒有 Roc 設定或 GitHub 登入時仍可開啟 Welcome，顯示待設定狀態而非退出。
  Status: passed
  Evidence:
  Fresh CLI fixtures verified Welcome remains open with setup guidance when settings are absent or GitHub authentication reads fail.
• 切換分頁或縮放視窗不遺失選中任務；GitHub 刷新失敗保留上一份資料並標示過期或錯誤。
  Status: passed
  Evidence:
  Fixtures and PTY checks preserved task identity/details across tab changes and resize; failed refresh retained prior data and displayed STALE plus the error.
• 原有 task board 的非 TTY 輸出仍可使用；退出或終端錯誤後恢復終端狀態。
  Status: passed
  Evidence:
  GitHub command tests verified non-TTY board output. Session fixtures covered input/output/render failures and pending reads; PTY quit checks observed mouse, cursor and alternate-screen restoration.
• 在 80×24 和 40×24 終端顯示 12 個任務，連按六次 J 後第七個任務及其狀態保持可見；寬版多欄布局同樣成立。
  Status: passed
  Evidence:
  Fresh 12-task fixtures and inspected PTY frames at 40×24, 80×24 and 120×24 showed the seventh selected card and ready status after six J presses.
• 翻頁後再使用 J/K 或上下方向鍵，以及從首項／末項循環選取時，選中卡片重新可見；手動翻頁本身不被強制拉回選取位置。
  Status: passed
  Evidence:
  Fresh tests covered manual paging without selection snap-back, J/K and arrow-key reveal, both wraparound directions, populated-column transitions and scrolled mouse hits at 40/80/120 columns.