Add TUI UI and CLI I/O tests

[WTW0313]

Context

Skillpack needs test coverage for the Ink TUI and the CLI process contract without coupling UI tests to provider scanning or user directories.

Agreed approach

• Split Terminal UI Tests from CLI I/O Tests.
• Terminal UI Tests render an injectable app surface with Ink Testing Library, shared inventory fixtures, fixed terminal sizes, normalized output, and a mock SkillManager.
• CLI I/O Tests exercise an injectable CLI runner for stdin/stdout, alternate screen buffer control, signal handlers, render lifecycle, and process exit.
• Keep only a thin process-level smoke test for the built binary.
• Use snapshots only for stable normalized golden frames; use semantic assertions for interaction behavior.
• First phase covers navigation, detail routing, search, help, terminal envelope states, and entry/confirmation state for toggle/update/remove/install flows.
• Do not run real provider mutations, external skills commands, system file manager opens, or real signals inside the Vitest process.

Implementation units

1. Test infrastructure:

   • Add ink-testing-library as a TUI devDependency.
   • Extract an injectable AppSurface while keeping App responsible for real manager initialization.
   • Extract runSkillpackCli for terminal lifecycle and process I/O.
   • Add TUI test harness, inventory fixtures, output normalization, and deterministic cleanup.

2. First tests:

   • Inventory initial frame snapshot.
   • Keyboard navigation, detail routing, search, help overlay.
   • Too-small terminal state.
   • Toggle/update/remove/install entry or confirmation state.
   • CLI I/O runner output ordering and lifecycle tests.

References

• ADR: docs/adr/0038-split-tui-ui-tests-from-cli-io-tests.md
• Test guide: packages/tui/tests/README.md

[WTW0313]

Implemented locally on branch refactor/ui-polish.

Completed scope:

• Added ink-testing-library to the TUI package.
• Added AppSurface so Terminal UI Tests can render with injected manager/config/terminal size without scanning user directories.
• Added runSkillpackCli so CLI I/O Tests can verify terminal control sequences, signal unmount, render lifecycle, and process exit through injected streams/process/render.
• Added TUI test README, inventory fixtures, mock SkillManager, render harness, ANSI/frame normalization, and keyboard helpers.
• Added Terminal UI Tests for inventory snapshot, keyboard navigation, detail routing, search, help overlay, too-small terminal snapshot, toggle mutation entry, remove confirmation, update check, and install entry.
• Added CLI I/O Tests for alternate screen lifecycle ordering, SIGTERM unmount, and terminal restoration on render lifecycle failure.

Verification:

• pnpm --filter skillpack-tui test
• pnpm test
• pnpm build

Note: no real provider mutations, external skills commands, system file manager opens, or real signals in the Vitest process are used by the new tests.

[WTW0313]

Committed implementation on refactor/ui-polish:

• Commit: 587e377 (test(tui): add terminal UI and CLI I/O coverage)
• Branch status: local branch is ahead of origin/refactor/ui-polish by 1 commit.

Verification completed before commit:

• pnpm --filter skillpack-tui test
• pnpm test
• pnpm build

The implementation keeps Terminal UI Tests and CLI I/O Tests separated as described in ADR 0038 and avoids real provider mutations, external skills commands, system file manager opens, and real signals inside the Vitest process.