test(06-16): add isolated perf channel and critical calculation perf

- vitest.perf.config.ts: include only *.perf.ts, mirror vite.config.ts aliases, 30s timeouts
- package.json: add test:perf script (test/test:ci untouched)
- damage.perf.ts: 3 cases (1000/10000/50000) warmup 3 + 20 samples, no assertions

package.json

@@ -7,6 +7,7 @@
         "dev": "tsx script/dev.ts",
         "test": "vitest",
         "test:ci": "vitest run",
+        "test:perf": "vitest run --config vitest.perf.config.ts",
         "test:data-node": "tsx script/test-data-node.ts",
         "preview": "vite preview",
         "declare": "tsx script/declare.ts",