v0.27.0

Mermaid diagrams

• Render simple fenced mermaid diagrams as terminal-native Unicode.
• Open complex diagrams in a workspace preview with zooming, panning, and system-app export.
• Render locally with bounded workers, resource limits, caching, cancellation, and source fallback.

Headless RPC mode

• Added kit --mode rpc for controlling Kit as a long-lived JSON-lines subprocess.
• Supports prompts, steering, follow-ups, cancellation, sessions, model selection, thinking levels, and streaming lifecycle events.
• Added persistent, existing-session, and ephemeral --no-session operation.

Scratchpad

• Exposed each session scratchpad as a normal Markdown file editable through the standard read, edit, and write tools.
• Kept panel edits and agent file changes synchronized with atomic persistence and conflict protection.

Code review

• Saved review comments now appear immediately as composer attachments.
• Pressing s submits the attached review immediately.
• Preserved newer drafts and attachments when submissions overlap or fail.

External plugins: migration required

• Replaced direct TypeScript plugins with the language-neutral JSON-RPC v1 protocol over stdio.
• External plugins now use a plugin.json manifest and may be implemented in any language.
• Added commands, tools, chrome contributions, sub-agents, system prompts, events, UI requests, cancellation, and tool interception to the protocol.
• Removed the legacy *.ts loader and @akonwi/kit/plugin export.
• See docs/features/plugins.md and docs/plugin-protocol/v1.md for migration instructions.

UI improvements

• Confirmation-dialog messages now render Markdown, including formatted code blocks.
• Fixed clickable plugin header and footer contributions.