[FEATURE] Steering instructions for continue session with summary

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When resuming a session via the CLI prompt that offers "Use summary," there's no way to specify what to preserve—unlike the in-session /compact command which accepts focus instructions. This leads to risks of loading what is not wanted, and leaving out what is needed.

Proposed Solution

It would be great if the resume prompt's summary option let users add optional steering, like:

Use summary to resume?
Focus on (optional): [auth flow, recent errors, etc.]

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_