Fix root/ files under dot-prefixed dirs not installed from GitHub URLs

[hyericlee]

Summary

• Fixes root/ directory files not installed when package is installed from GitHub URL #43 — root/ directory files containing dot-prefixed path segments (e.g. root/.opencode/plugins/qmd-hooks.ts) were silently skipped when installing from a GitHub URL, but worked from local paths
• Root cause: minimatch(path, "**") returns false for paths with dot-prefixed segments (like .opencode/) unless {dot: true} is passed. GitHub installs set matchedPattern = "**" via computePathScoping; local installs never set it, so the filter was inactive
• Introduces a centralized matchPackagePath utility that wraps minimatch with {dot: true} and replaces bare minimatch() at all 4 affected call sites