fix(opencode): move frontmatter parser out of plugins/ directory (#596)

[prayag0one4]

Problem

Loading the ponytail OpenCode plugin (@dietrichgebert/ponytail, installed via "plugin": ["@dietrichgebert/ponytail"]) fails at plugin-load time with:

error="path must be a string or a file descriptor"
error="The \"path\" argument must be of type string or an instance of Buffer or URL. Received an instance of Object"

Root Cause

ponytail-frontmatter.cjs lived inside .opencode/plugins/, which OpenCode's legacy plugin loader scans for modules. It found parseCommandFile exported from that file and tried to call it as a plugin, passing the plugin context object { client: ... } as the filePath argument to fs.readFileSync. This is a recurrence of #301 — the extraction worked for ponytail.mjs exports but the file stayed in the scanned directory.

Fix

Moved ponytail-frontmatter.cjs from .opencode/plugins/ to .opencode/ (outside the scanned directory), updated the two require paths. The plugins/ directory now contains only ponytail.mjs with its single default export.

Verification

• All 8 OpenCode plugin tests pass
• Legacy loader simulation shows zero errors — plugins/ only contains the plugin function, nothing else to mistakenly invoke
• package.json files field uses .opencode/ directory glob, so the moved file is still included in the npm package

Closes #596

[Copilot]

Pull request overview

Fixes OpenCode plugin-load failures caused by OpenCode’s legacy plugin loader mistakenly discovering and invoking parseCommandFile as a plugin when it lived under .opencode/plugins/.

Changes:

• Moved the frontmatter parser module out of .opencode/plugins/ so the legacy loader won’t discover it.
• Updated the OpenCode plugin module to require() the parser from its new location.
• Updated tests to import the parser from the new path.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
tests/opencode-plugin.test.js	Updates the direct require() path for parseCommandFile to match the parser’s new location.
.opencode/ponytail-frontmatter.cjs	Keeps the parser module outside .opencode/plugins/ and updates comments to reflect the loader behavior and incident.
.opencode/plugins/ponytail.mjs	Updates the relative require() path so the plugin uses the relocated parser module.