feat: establish simulation scaling baseline

docs/LEARNING_ROADMAP.md

@@ -467,7 +467,10 @@ a smaller active population remains fully represented. Moving an NPC between
 fidelity levels preserves identity, inventory, task, relationships, and
 important history.
 
-Set the target population only after collecting baseline measurements.
+[Simulation scaling baseline 01](benchmarks/SIMULATION_SCALING_BASELINE_01.md)
+sets the first local target at 600 data-only full-fidelity NPCs while preserving
+deterministic state. Revisit that target when world presentation or LOD enters
+the measured workload.
 
 ## Milestone 9 — Player interaction and social agency
 
@@ -849,14 +852,29 @@ cared-about shortage now produces an inspectable opportunity whose NPC and
 player responses both use the originating resource, relationship, knowledge,
 and event systems rather than quest-only duplicates.
 
-The immediate next slice should begin Milestone 8 with a deterministic headless
-scaling baseline: measure tick throughput, serialized-state growth, and retained
-history across increasing NPC/event counts using the current full-fidelity
-simulation. Set an evidence-backed target before adding spatial partitions,
-batching, or active/abstract LOD transitions.
+The first Milestone 8 measurement slice is complete. A reusable schema-valid
+headless fixture and CLI runner now measure three fresh deterministic samples
+across 6, 60, and 600 NPCs plus 600 and 6,000 seeded event histories. The
+reviewed Apple M1 Max baseline reaches 65.84 ticks per second at 600 NPCs, but
+10x population from 60 to 600 costs about 24.4x per tick and creates 20,950
+objective events over 200 measured ticks. The machine-readable samples,
+workload exclusions, checksums, and local 50-ticks-per-second reference target
+live in
+[Simulation scaling baseline 01](benchmarks/SIMULATION_SCALING_BASELINE_01.md).
+
+The immediate next slice should build one bounded per-tick population view for
+the existing trusted-starving-subject query. That scarce-food path currently
+rebuilds an all-NPC lookup for each applicable idle decision, making it the
+first code-level candidate consistent with the measured superlinear growth.
+Preserve exact selection/checksum behavior and rerun the same ledger before
+choosing a spatial index or active/abstract LOD design.
 
 Recently completed:
 
+- Deterministic simulation scaling baseline: schema-valid full-fidelity
+  fixtures, a repeatable CLI runner, and a fast headless regression now record
+  population throughput, phase timing, serialized-state growth, history
+  retention, event growth, and deterministic checksums before optimization.
 - Simulation responsibility cleanup: storage/inventory transactions now live
   in `VillageEconomy`, ordered history and rate queries live in
   `SimulationEventLog`, and `SimulationManager` exposes a shorter tick