Phase 4 Priority 2 & 3 Final Plan Summary

Implementation Approach: Sequential (1→2→3→4) over 5-8 days for maximum safety
go/types Handling: STRICT - Compilation fails with clear error if go/types.Info unavailable
Guard Validation: STRICT - Invalid guards cause compile errors (boolean type check)
Guard Scope: RELAXED - Allows outer scope variable references (e.g., threshold from parent scope)

Task Breakdown:
1. Implement 4 context type helpers (2-3 days) - Foundation for 90%+ None inference
2. Pattern match scrutinee go/types integration (1 day) - Accurate type detection for aliases
3. Err() context-based inference (1-2 days) - Eliminates Result_interface_error
4. Guard validation with outer scope (1-2 days) - Complete guard support, remove 2 TODOs

Key Decision: No fallback mode. If go/types unavailable, fail fast with actionable error.
Success Metrics: None coverage 50%→90%, pattern accuracy 85%→95%, Err() correctness 0%→80%

All infrastructure exists. Implementation is straightforward with thorough validation checkpoints.
