[FEATURE] Show AI-generated micro-recaps in welcome screen "Recent activity" instead of raw last prompts

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

The welcome screen "Recent activity" list currently shows the last user prompt from each recent session (e.g. run it, reprint, continue on DDS). For anyone with a few parallel workstreams, these are ambiguous — I
can't tell which session did what without /resume-ing into each one.

Proposed Solution

Replace (or augment) each entry with a one-line AI-generated recap summarizing what the session accomplished and/or what's pending. Example:
▎
▎ Current:
▎ 1d ago run it
▎ 1d ago reprint
▎ 1d ago continue on DDS
▎
▎ Proposed:
▎ 1d ago Tagged SREP-15 PDP w/ journey-label guard; pending QA-AFS run
▎ 1d ago Reprinted DDS perf baseline table (7 profiles, post-index-fix)
▎ 1d ago Merge DDS prod smoke — FW26=16K articles, SS26=0 (M3 dep)

▎ The recap could be generated at session-end (on /clear, exit, or compaction) and cached on the session record so it doesn't cost extra tokens at welcome-screen render time.

▎ Makes /resume actually useful as a session-picker rather than a guessing game. Especially valuable for long-running Claude Max users juggling several parallel projects/workstreams.

Alternative Solutions

_No response_

Priority

High - Significant impact on productivity

Feature Category

CLI commands and flags

Use Case Example

_No response_

Additional Context

_No response_