This commit introduces a new, more stable footer architecture that addresses
several long-standing UX issues:
- Stabilizes the layout by anchoring mode indicators and context summaries
- Protects safety indicators (YOLO/Plan) from being hidden by notifications
- Decouples ambient tips/wit from real system status to prevent confusion
- Implements intelligent collision detection for narrow terminal windows
- Keeps input visible but disabled during tool approval pauses
- Enhances visual consistency with unified status colors and hook icons
