Adds `make perf-baseline` — boots the full server plugin stack with
real content, measures 50 ticks (5 warmup), captures per-tick timing,
entity counts, and process RSS. Includes shadowcast benchmarks. Saves
structured JSON to tests/perf/baseline.json for regression detection.
Supports --compare mode (>20% threshold).
First baseline: mean 366µs, p95 526µs (0.5% of D-026 100ms budget).
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Create client/, server/, tooling/, tests/, .config/ (tracked) and
.cache/ (gitignored). Update CLAUDE.md project structure to reflect
the new layout including workshops directory.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>