Sprint 257 Plan: Top-Gap Uplift Hard Gate

Goal

Convert top-gap weighted raw scoring from advisory telemetry into an enforceable policy gate so non-improving raw-only runs fail fast.

Step 2332: Add raw top-gap uplift gate env control.
Step 2333: Fail raw search when weighted top-gap mode is not properly configured.
Step 2334: Fail raw search when best top-gap score does not improve baseline.
Step 2335: Emit top-gap uplift gate policy fields in raw search summary.
Step 2336: Add Sprint257IntegrationSummary.h and execution tracker.