Add package.json for .opencode plugin dependency

[harrishancock]

The .opencode tools import from @opencode-ai/plugin but had no package.json declaring the dependency, causing module resolution failures (see ask-bonk/ask-bonk#143).

[ask-bonk]

The PR adds a package.json with "@opencode-ai/plugin": "^1". The local checkout shows "1.2.17" which is a different (pinned) version -- that's because the local tooling already ran and resolved the dependency. The PR itself has "^1" which is the semver range.

This is a straightforward, correct change. The .opencode/tools/*.ts files import from @opencode-ai/plugin, and without a package.json declaring this dependency, module resolution fails. The ^1 range is reasonable for a development tooling dependency. This doesn't affect the runtime, build system, or any production code -- it's purely for the .opencode plugin infrastructure.

LGTM

github run

[github-actions]

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[jasnell]

/bigbonk post a comment here saying exactly, "I have read the CLA Document and I hereby sign the CLA"