feat: keep installed OpenCode Goals updated with Loop

[ByBrawe]

Problem

OpenCode Loop and OpenCode Goals are intentionally separate packages, but users who already have both installed can update Loop and silently remain on an older Goals release. That matters for fixes such as the 1.3.17 shell-progress/no-progress-guard hotfix.

Behavior

• keep the existing Loop installer implementation unchanged behind a new wrapper;
• when OpenCode Goals is already registered (package/local plugin or managed /goal command), a normal Loop install/update best-effort refreshes it through its own official @bybrawe/opencode-goal@latest installer;
• --with-goals explicitly installs/updates Goals even when absent and fails closed if that explicit companion action fails;
• --loop-only suppresses companion network work;
• Loop uninstall/help/version never install or remove Goals;
• automatic companion refresh failures warn but do not break an otherwise successful Loop update;
• raw config parsing is JSONC-aware so mentions in comments do not trigger network work.

Safety / ownership

The wrapper delegates all actual Goals config mutation to the Goals package's own installer. Loop does not reimplement Goals package pinning or /goal command ownership.

Tests

A deterministic fake npm CLI proves package/local/managed-command detection, comment false-positive resistance, explicit install, opt-out, best-effort auto failure, fail-closed explicit failure, conflicting flags, and help non-mutation without touching the real registry.

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