fix(coding-agent): resolve Termux env shebang hops

[jinon86]

Summary

• resolve env-based CLI shebangs through PATH in the ccc-node launcher
• invoke the pinned tsx module through the resolved Node binary in the source launcher
• cover unavailable /usr/bin/env, safe env -S arguments, shell-syntax rejection, and the tsx hop

Why

Android/Termux does not provide /usr/bin/env. When ccc-node intentionally strips the libtermux-exec LD_PRELOAD hook for an isolated subprocess, both Piri's CLI shebang and the source launcher's .bin/tsx shebang can fail before Node starts. This completes the Piri-side work tracked by jinwon-int/ccc-node#1184.

Validation

• node --test scripts/piri-ccc.test.mjs (8/8)
• bash -n scripts/piri-ccc.sh pi-test.sh
• git diff --check
• npm run check

Per repository instructions, the full npm test suite was left to CI.

This pull request was prepared with Codex.

[seoseo-ai]

Reviewed exact head c0b0e513d2686c5ea7357984a83074b99c92daa6.

• The launcher resolves only env shebangs and passes arguments as arrays without shell evaluation.
• env -S fixed arguments are allowlisted; shell syntax is rejected and covered by a non-execution regression test.
• The source launcher resolves node through PATH and invokes the pinned tsx module directly, removing the second /usr/bin/env hop.
• CI build-check-test and check-contributor are green at this head.

Approved with no blocking findings.

This review was prepared with Codex.