Implement Layer 3: Big Five personality analysis system

Layer 3 evaluates the user based on their Layer 2 memories using the
Big Five personality model (OCEAN), which is the most reliable
psychological model for personality assessment.

Changes:
- Add UserAnalysis struct with Big Five traits (Openness,
  Conscientiousness, Extraversion, Agreeableness, Neuroticism)
- Create user_analyses table in SQLite for storing analyses
- Add storage methods: save_analysis, get_latest_analysis, list_analyses
- Add MCP tools: save_user_analysis and get_user_analysis
- Include helper methods: dominant_trait(), is_high()
- All scores are f32 clamped to 0.0-1.0 range

Architecture:
- Layer 3 analyzes patterns from Layer 2 memories (AI interpretations
  and priority scores) to build psychological profile
- AI judges personality, tool records the analysis
- Independent from memory storage but references Layer 2 data

src/core/mod.rs

@@ -1,7 +1,9 @@
+pub mod analysis;
 pub mod error;
 pub mod memory;
 pub mod store;
 
+pub use analysis::UserAnalysis;
 pub use error::{MemoryError, Result};
 pub use memory::Memory;
 pub use store::MemoryStore;