Drop gtb turbo's Android escape hatch for the npm turbo

[gtbuchanan]

Summary

vercel/turborepo#12735 shipped in turbo 2.10.8, publishing the linux-arm64 binary under os: ["android", "linux"]. node_modules/.bin/turbo now starts on Termux, so gtb turbo no longer resolves a pkg install turbo binary from $PREFIX/bin/turbo.

That fixes the launcher, but not how turbo spawns tasks. The npm binary is statically linked (no PT_INTERP), so Termux's libtermux-exec-ld-preload.so shebang rewriter never loads into it and execve on $PREFIX/bin/pnpm hits its literal #!/usr/bin/env node, which Android has no /usr/bin/env for. @gtbuchanan/pnpm-termux-shim remains the fix for that — it moves from a defensive dependency to the mechanism the npm turbo depends on, so this repo now dogfoods it as a workspace-root optionalDependency.

Why gtb turbo still exists

Installing the shim is what makes the wrapper load-bearing. turbo resolves the package manager against PATH from the directory it was invoked in, keeps the path that search produced, then runs each task with that package's directory as the cwd — so a match from a relative entry is re-interpreted against the child's directory and the spawn fails. pnpm always prepends a relative ./node_modules/.bin, which is exactly where the shim installs its pnpm.

gtb turbo now rewrites every PATH entry to an absolute path before invoking turbo. Isolated on-device:

PATH entry 1	pnpm at <root>/<entry>	pnpm at <pkg>/<entry>	Result
./packages	no	no	falls through to the absolute entry ✅
./relbin (probe)	yes	yes	ran the package-dir copy, not the one turbo picked ⚠️
./relbin (probe)	yes	no	unable to spawn child process, absolute entry never tried ❌

Non-Android hosts are unaffected either way: the shim's os filter means nothing named pnpm occupies node_modules/.bin, so the relative entry never matches and the normalization is a no-op.

Verification

• Full pnpm build --concurrency=1 on Termux/aarch64: 73/73 tasks, gtb verify clean
• pnpm run gtb turbo run typecheck:ts exercises the real pnpm-injected PATH end to end
• 8 unit tests for withAbsolutePathEntries, written before the implementation and confirmed failing first

Notes

• Docs updated: gtb-build-pipeline skill (Android-Termux section, description, and two evals that encoded the removed behavior), both package READMEs, CONTRIBUTING.md, and AGENTS.md
• AGENTS.md's "Why turbo isn't in mise.toml" reasoning is unchanged — #12735 widened the os field of the existing npm package rather than adding standalone release binaries, so mise still has no backend with per-platform integrity
• The shim README's mechanism was corrected: the binary is statically linked, not glibc-built as previously documented

🤖 Generated with Claude Code

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Codecov Report

❌ Patch coverage is 77.77778% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.87%. Comparing base (feae032) to head (d93b0da).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/cli/src/commands/root/turbo.ts	77.77%	1 Missing and 1 partial ⚠️

❌ Your patch status has failed because the patch coverage (77.77%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

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