[Feature]: Add support for completions

[ericanderson]

Issue Type

• ✨ feature - New feature (non-breaking change which adds functionality)
• ⚡ performance - Performance improvement
• 🖥️ backend - Backend-related feature
• 🎨 frontend - Frontend-related feature

Component Scope

Both Frontend and Backend

Problem Statement

Being able to type / in the terminal ui and see my commands is a huge win. Same with being able to @ a file or an agent. My understanding is that MCP servers also can support completions.

Proposed Solution

It really depends on what the claude code npm module supports. If its "dumb" then i would implement a backend feature for getting completions where you specify type is "command" | "@" and pass it the text you have. Then the front end could simply see the slash or at character, collect the extra letters and present the UI.

If the backend is "smart" then it might be as simple as a backend call that exposes the text and the cursor location.

Use Cases

No response

Alternatives Considered

No response

Priority

Medium - Would significantly improve my workflow

Implementation Complexity (if known)

Simple - Small change or addition

Implementation Considerations

No response

Examples or Mockups

No response

Contribution

• I would be willing to implement this feature myself
• I would be willing to help test this feature
• I would be willing to help with documentation
• I would be willing to provide feedback during development

Additional Context

No response

Checklist

• I have searched existing issues and feature requests to make sure this is not a duplicate
• I have provided a clear problem statement and proposed solution
• I understand that feature requests are prioritized based on community needs and maintainer capacity