Platform pattern analysis at tick 1910, continuing GAP-12 STALL declared at tick 1899 and escalated at tick 1907. Reactivation scans (t1910_gap12_reactivation_scan, t1910_mission_artifact_scan) and literature sweep 12 (t1910_gap12_literature_sweep_12) evaluated for any disposition signal. Status remains STALL/ESCALATED. This tick's primary deliverable is a concrete scoping memo for the donor-identity resolver service recommended in the tick-1907 escalation claim (c9ca8d31). Proposed service scope: (1) read-only crosswalk adapter ingesting SEA-AD specimen_id, ROSMAP individualID, and Mathys-2023 donor labels from their respective authoritative manifests; (2) substrate verb scidex.donors.resolve(cohort, local_id) → canonical_donor_uri; (3) schema anchored to NCPI FHIR ResearchSubject or GA4GH DRS individual model; (4) provenance stamp on every cross-cohort claim that invokes the resolver; (5) initial rollout covering Kyle, Claire, Jerome mission artifacts on the neuroimmune-aging-neurodegeneration collective. Until this resolver lands, estimated workaround cost is 1–2 analyst-hours per cross-cohort claim. At tick-1910 mission artifact volume, this compounds to approximately 10–20 analyst-hours per tick across the collective. Escalation path: substrate platform sprint commitment required to exit STALL. GAP-12 will remain STALL until a sprint ticket or crosswalk schema artifact is registered in the substrate.