fix: make prefix mode work on Windows

[hyldmo]

Proves numux --prefix on Windows for parallel verify-style DAGs and fixes everything found.

What was broken (each proven on a windows-2025 runner)

1. bun run docs crashed: Windows checks out CRLF, the marker regex expects LF (Marker not found: subcommands).
2. Segfault at startup: static import of ghostty-opentui native code crashes Bun 1.3.12 on Windows (exit 3 in ~100ms), even for --prefix.
3. Spawn hung: Bun PTY terminal spawn is POSIX-only on 1.3.12; one run hung to the 10-minute timeout.
4. Exit codes silently became 0: Bun MSVCRT-style argv escaping mangles inner quotes for cmd.exe, so bun -e "..." ran as bare bun. Failure detection was fully broken.

Changes

• src/index.ts: TUI loads via dynamic import only in TUI mode; exec uses the shared shell helper; logs <proc> streams the file in chunks instead of spawning cat.
• src/process/runner.ts: win32 spawns cmd with piped stdio pumped into the existing handlers; direct kill instead of negative-PID group kill. POSIX path untouched.
• src/utils/shell.ts (new, tested): shellArgv (sh -c vs Node-style cmd /d /s /c "cmd") and shellSpawnOptions (windowsVerbatimArguments, which is what preserves quotes and exit codes).
• scripts/generate-docs.ts: CRLF-tolerant reads. .gitattributes: eol=lf, matching the Biome LF rule.
• CI: new windows-prefix job running scripts/windows-prefix-smoke.ts (parallel DAG + dependsOn ordering + failing exit code + skip propagation, all bun -e commands); workflow_dispatch trigger; commitlint PR-only.

Proof

Green run (check + windows-prefix, 10/10 smoke assertions on win32): https://github.com/hyldmo/numux/actions/runs/34586422554

Caveat: only prefix mode is proven. The TUI still loads native modules that crash Bun on Windows, so recommend --prefix there.

[github-actions]

🎉 This PR is included in version 2.19.1 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀