feat: establish simulation scaling baseline

docs/benchmarks/README.md

@@ -0,0 +1,23 @@
+# Simulation benchmark ledger
+
+This directory stores reviewed benchmark snapshots. Each snapshot must name the
+workload, seed, Godot version, hardware context, sample count, simulated tick
+count, and important exclusions so later comparisons remain honest.
+
+Run the current scaling harness from the project root with Godot 4.7:
+
+```bash
+/Applications/Godot.app/Contents/MacOS/Godot \
+  --headless --path "$PWD" \
+  --script res://tools/benchmark_simulation_scaling.gd
+```
+
+The default report is written under `user://`. Pass
+`-- --host-label="<hardware>" --output=res://docs/benchmarks/<name>.json` only
+when intentionally capturing a reviewed project baseline.
+
+Reviewed captures:
+
+- [Simulation scaling baseline 01](SIMULATION_SCALING_BASELINE_01.md) records
+  the first full-fidelity population/history measurements and the bounded next
+  optimization.