PHASE2_UNIFIED_STRATEGY.md

PHASE2_UNIFIED_STRATEGY.md defines the pipeline design and tool justifications for processing Phase 2 file types Opus 4.6 created the PHASE2_UNIFIED_STRATEGY.md which contains pipeline design, tool justifications, and question-to-data mapping. The PHASE2_UNIFIED_STRATEGY.md and PHASE2_IMPLEMENTATION_PLAN.md documents contain complementary research outputs informing Phase 2 implementation decisions.