Publish npm releases with GitHub Actions OIDC

[yourcasualdev]

Summary

• add a publish.yml workflow triggered by published GitHub Releases
• use npm Trusted Publishing through GitHub OIDC instead of a long-lived npm token
• verify the release tag exactly matches package.json before publishing
• run the full test, typecheck, and build suite before npm publish
• prepare version 0.1.2 and its changelog entry

Validation

• bun run check
• workflow YAML parse
• npm publish --dry-run --json

One-time npm setup

Configure the npm package trusted publisher for:

• GitHub owner: yourcasualdev
• Repository: opencode-cliproxyapi
• Workflow: publish.yml
• Allowed action: npm publish

After this PR is merged, publishing GitHub Release v0.1.2 will publish the package.