Implementation plan complete for all 4 priorities. Detailed 11-16 hour roadmap created with parallel execution strategy: Priority 1 (fix non-deterministic switch cases) and Priority 4 (return statement None inference) can run in parallel first, then Priority 2 (preprocessor bugs) requires deterministic output, followed by Priority 3 (integration tests). Expected outcome: 98-100% test passing (275-280/280 tests). Zero blocking questions - ready to execute Phase 1.
