Feat/opencode configuration

[Jakub-Vacek]

This PR adds complete Open Code configuration. Most important files are index.ts, package.json and ci/cd publish yaml.
OpenCode has different approach to plugins - plugins are NPM packages that set up Open Code instance (including agents/skills/rules/MCP and even ENVs) to use specific capabilities. Actual package is basically one file that provides Plugin type (defined by open-code SDK) and dependencies definition in package.json

Dependencies of this PR
NPM_TOKEN GitHub secret must be set on this repo
Internal repo token will likely has to be updated to have rights to write content to this repo.

Testing the Open Code plugin
There are two levels of testing:

• index.ts testing that the file actually works - make sense only for internal (DXH) testing
• Complete flow - needs actual public package to test the whole flow

Intended flow from OpenCode perspective:

1. User directly sets two rows in their opencode.json or run open code client command => Apify package (published from this repo) is mentioned in opencode.json
2. When open code is started it uses code from package to set up the environment

Intended flow from Apify perspective:

1. Internal repo (https://github.com/apify/apify-plugins-internal) we "feed" actual agent/skill/rules to this repo (using internal repo CI/CD). Same as for other platforms
2. On release (so manual decision) new version of this package is released
3. Users use that package to "set up" the open code to use Apify

[Copilot]

Pull request overview

This PR scaffolds an Apify plugin package for Open Code, including TypeScript configuration, package metadata/docs, and a GitHub Actions workflow to publish the plugin to npm on GitHub Releases.

Changes:

• Adds an Open Code plugin entrypoint (index.ts) that configures the Apify MCP server, agent prompt, skills path, tool allowlist, and env passthrough.
• Introduces npm packaging metadata (package.json), TypeScript config (tsconfig.json), and release-time publishing workflow (.github/workflows/publish.yml).
• Adds project documentation and release metadata (README.md, CHANGELOG.md, LICENSE, .gitignore).

Reviewed changes

Copilot reviewed 6 out of 8 changed files in this pull request and generated 9 comments.

Show a summary per file

File	Description
index.ts	Plugin entrypoint that wires MCP/agent/skills/instructions into the Open Code config.
package.json	Declares the npm package and its published files/scripts/dependencies.
tsconfig.json	TypeScript compiler configuration for the plugin entrypoint.
.github/workflows/publish.yml	Publishes the package to npm on GitHub Release publication.
README.md	User-facing installation/usage docs for the Open Code plugin.
CHANGELOG.md	Initial changelog entry for v1.0.0.
LICENSE	Apache-2.0 license text.
.gitignore	Ignores node_modules.

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[Copilot]

Pull request overview

Copilot reviewed 6 out of 8 changed files in this pull request and generated 6 comments.

[jirispilka]

I'm not sure how it should work but the README could be improved.
It is kind of mixing MCP, CLI, and SKD integration, which is a bit confusing at a first glance.

I understand it now but I was confused at the beginning.

Otherwise it looks ok.