Core changes:
- Add AI interpreter module for content interpretation and priority scoring
- Extend Memory struct with interpreted_content, priority_score (f32: 0.0-1.0), and user_context
- Implement automatic memory pruning based on priority scores
- Add capacity management (default: 100 memories max)
- Create comprehensive design documentation
Technical details:
- Changed priority_score from u8 (1-100) to f32 (0.0-1.0) for better AI compatibility
- Add create_memory_with_ai() method for AI-enhanced memory creation
- Implement get_memories_by_priority() for priority-based sorting
- Score evaluation criteria: emotional impact, user relevance, novelty, utility
Philosophy:
This implements a "psychological priority memory system" where AI interprets
and evaluates memories rather than storing raw content. Inspired by how human
memory works - interpreting and prioritizing rather than perfect recording.
