09 — Scale Not Safe (explicit, still blocking)

Scale is NOT solved in this layer and is not hidden. v_qt001_scale_not_safe_guard_v2: keyset_resume_scanner_objects=0 (no fn_qt001 keyset/resume/watermark/scanner exists), v1_scale_not_safe=true, scale_not_safe=true, scale_absent_confirmed=true, pass=true. Evidence: fn_qt001_plan_all performs a per-row EXISTS over birth_registry for every source row across 74 collections (~5s; system_issues ~223,952 rows; the live MCP 5s timeout cancels it — reproduced this session). There is no keyset/watermark resume, no automatic refresh scanner, and no representative-volume perf gate.

Scale remains a blocking APPLY gate in readiness v5 (scale_safe=false) and a documented blocker (matrix #13, ROUTED_2_6B_BLOCKING). It is deferred to 2.6B/2.6C where keyset/watermark resume + perf gates will be built, but until then apply cannot proceed on scale grounds alone.