Use native Codex Cloud environment and remove Codex-specific launcher test

[max-sixty]

Motivation

• Codex Cloud environment setup should use the platform's native toolchain behavior instead of a repository-specific UID-switching Cargo wrapper and interposed tini logic.
• The repository-owned Codex Cloud launcher synchronization test is repository-specific and unnecessary for usual CI runs and causes coupling between documentation launchers and test suite mechanics.

Description

• Removed the Codex Cloud launcher synchronization integration test in tests/integration_tests/readme_sync.rs so README/Taskfile launcher checks no longer assert a repo-specific launcher string.
• Simplified scripts/codex-cloud/Taskfile.yaml to stop creating a UID-switching cargo wrapper, drop tini usage, and avoid enforcing the ubuntu UID 1000 precondition; the Taskfile now prepares and runs Rustup, pre-commit, and Cargo directly using the native environment.
• Removed chown/chmod dance targeting the ubuntu user and replaced those with straightforward directory creation and native rustup/pre-commit invocations in prepare-codex.
• Updated scripts/codex-cloud/README.md to reflect the new Taskfile behavior and refreshed the documented TASKFILE_SHA to match the updated Taskfile.

Testing

• Ran cargo test --test integration test_taskfile_llm_commands_match_config_example and it passed (1 passed).
• Verified Taskfile parsing with task --taskfile scripts/codex-cloud/Taskfile.yaml --list and it succeeded.
• Verified documented launcher checksums by checking TASKFILE_SHA lines in scripts/codex-cloud/README.md match sha256sum scripts/codex-cloud/Taskfile.yaml and the checks passed.
• Ran git diff --check and basic repo hygiene checks and they passed; note that python3 -c 'import yaml' failed due to PyYAML not being installed in the environment, but task itself successfully parsed the YAML, so Taskfile syntax was validated.

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Codex Task

[worktrunk-bot]

Reviewing as a draft — flagging anything that looks worth a quick fix. Mark ready for a full review.

Two things, one of which I think blocks the environment doing its job.

Running the suite as root will fail three tests. Dropping the UID-1000 switch means the README's own validation command (cargo run -- hook pre-merge --yes) now runs as root, and three tests in tests/integration_tests/step_copy_ignored.rs derive their expected failure purely from a 0o555 directory, with no root guard: test_copy_ignored_error_includes_path_directory, test_copy_ignored_error_includes_path_file, and test_copy_ignored_error_nested_file_parent_creation. Each chmods the destination to 0o555, runs wt step copy-ignored, and asserts !output.status.success() — under CAP_DAC_OVERRIDE the copy succeeds and the assertion fires. The repo already treats this as a known shape elsewhere: test_configure_shell_fish_legacy_remove_failure_warns in tests/integration_tests/configure_shell.rs probes with a scratch write and bails out with eprintln!("Skipping - running with elevated privileges") when permissions don't restrict, and remove.rs, approval_pty.rs, and approval_save.rs carry the same guard. The three copy_ignored tests never needed it because the Cargo wrapper kept them off root — which is what the deleted README line about "the suite's permission and child-reaping assumptions" was pointing at. If native behavior is the goal, the same guard on those three (or a verified full-suite Cloud run) is the missing piece; #3810 validated with hook pre-merge --yes in Cloud, and the Testing section here covers one test plus task --list.

Related but not a failure: test_list_full_survives_read_only_object_database and test_list_statusline_survives_read_only_object_database in list.rs freeze .git/objects by stripping write bits, so as root they pass without ever reaching redirect_objects_if_read_only. The coverage doesn't break, it just stops existing in this environment.

The deleted digest test is the only thing enforcing a gate the README still depends on. See the inline comment.

On tini — the paragraph being removed cited child-reaping, and the PR body drops it without saying whether that was load-bearing (zombies actually observed under cargo nextest) or belt-and-braces. Worth stating either way, since it's the one removal with no direct replacement.

Last, a judgment call rather than a rule I can point at: these are two independent changes — the digest test removal doesn't depend on the environment simplification, and either could be reverted without the other — so they'd land more cleanly as separate PRs.

[worktrunk-bot]

Removing this test leaves the digest gate documented but unenforced. scripts/codex-cloud/README.md still says "The hash prevents a task branch from changing code run as root. After a reviewed Taskfile change reaches the default branch, update both environment commands", and the weekly-maintenance entry in .claude/skills/running-tend/SKILL.md still instructs "copy the Taskfile's new digest into both README launchers" for the Codex Cloud tools. With the test gone, the next Taskfile edit that forgets the README produces a mismatch that surfaces only inside Codex Cloud, at sha256sum -c - before anything runs, with no CI signal at all — and the Testing section of this PR did that comparison by hand, which is precisely what the test automated.

The TASK_VERSION extraction is the part that couples this to Taskfile internals; the digest assertion alone doesn't. If the coupling is the objection, dropping the regex and keeping the sha256sum-equivalent check would keep the guard at a fraction of the surface. Worth having a reason to lose it entirely, given the failure it catches is invisible to every check that runs here.

[max-sixty]

Closing as a duplicate of #3835 — the two diffs are byte-identical. Keeping #3835 as the single home for the run-as-root proposal.

This was written by Claude Code on behalf of max-sixty