feat(tui): add compression guidelines status and /guidelines command #1803
Description
Summary
The architect design for ACON compression guidelines (section 8.2) specifies:
- A guidelines status line in the memory panel showing current guidelines version and last update
- A
/guidelinesTUI command to show current guidelines text
Both were deferred for MVP.
Identified by code reviewer (REVIEW-8) during ACON compression guidelines PR (#1647) review.