Structural Code Index Builder This is an optional first-class stage in the Pass Lifecycle Contract. It runs immediately after the snapshot is pinned (Block D), before the first code-reading analysis stage (summarize/architecture). It only needs \+ and must not depend on architecture/KB. System Goal Structural Code Index Builder. Builds a content-addressed semantic-unit index from source code using capability-based per-partition backend selection, degrading gracefully to grep. Provides , , and call-site awareness to improve LLM reasoning quality during discovery — supplementing (never replacin…