fix: release Code Context plugin updates as 0.2.7

[alphali]

Summary

Plugin changes merged after 0.2.6 reused the same manifest version, so existing Claude Code installations could retain cached content instead of receiving the follow-up and journey fixes. Bump all three host manifests, the package, release verifier, and local helper client identity to 0.2.7 so those changes are available as a distinct update.

Document checking the Doable plugin version, explicitly updating a user-scoped Claude Code installation, loading it into a session, and enabling marketplace auto-updates. Add release notes for the already-merged behavior included in this release.

Privacy and compatibility

No new network calls, credentials, schema changes, or workflow changes. Existing state and business logic are unchanged apart from the local helper's reported client version. This release does not claim to fix malformed model-generated tool arguments or model response stream interruptions.

Verification

• npm test — release verification and both existing helper integration tests passed with Node.js 22.22.1.
• claude plugin validate ./plugins/doable-code-context — passed with Claude Code 2.1.274.
• git diff --check — passed.
• No credentials, customer data, private URLs, local paths, or .doable/ state included.
• Documentation and manifests updated.

Not tested: an installed customer's upgrade and active-session reload, or a live Doable round. The version is not yet published on main, and no customer state was changed. Fresh host installation/upgrade verification remains a release follow-up.