Use resilient GrumPHP binary resolution in packaged git hooks

[coisa]

Context

Current packaged hooks invoke vendor/bin/grumphp.phar directly. This fails for global installs of fast-forward/dev-tools, where local repository vendor/ may not contain that phar.

Goal

Make hook invocation path-agnostic so hooks work in both local and global DevTools setups.

Acceptance criteria

• Hook templates no longer use a hardcoded vendor/bin/grumphp.phar path.
• Hooks first prefer local ./vendor/bin/grumphp when available.
• Hooks fall back to ./vendor/bin/grumphp.phar for compatibility.
• Hooks fall back to grumphp from PATH when no local executable exists.
• Existing local/managed config behavior (./grumphp.yml > managed config fallback) is unchanged.
• Add/update tests/docs if hook-template expectations change.

Relation

This is an intermediate fix prior to full extraction for #296.

[coisa]

Created this as the intermediary fix for issue #296.

Working branch: chore/331-fix-git-hooks-grumphp-binary.
Commit: 5084336

The hook templates now resolve GrumPHP execution without hardcoded vendor/bin/grumphp.phar in the packaged scripts.