Sprint 264 Plan: Raw Score/Gate Parity Alignment

Goal

Eliminate scorer-vs-gate semantic drift by ensuring downstream coverage checks evaluate the same selected raw candidate task set used by raw scoring.

Step 2368: Persist selected raw candidate tasks back into generation artifacts.
Step 2369: Re-run hard sample with structural projector to verify score/gate parity.
Step 2370: Confirm native_raw_candidate_search and native_impact_coverage agree.
Step 2371: Add Sprint264IntegrationSummary.h and execution tracker.