memory-gate

Memory-First Gate (BLOCKING) and the Chesterton's Fence investigation protocol, split out of the memory router per ADR-063. Forces a memory search before you change existing code, constraints, or protocol, so the "why" is recovered before the fence comes down. Use when you say memory-first gate, search memory before changing, or chesterton fence check. Do NOT use for plain Tier 1 lookups (use memory-search) or…