ci(test): perf and scale benchmarks leave the correctness gate

tests/configs/vitest.perf.config.ts

@@ -0,0 +1,56 @@
+import { defineConfig } from 'vitest/config'
+
+/**
+ * Perf/scale + environment-dependent test configuration.
+ *
+ * The exclusive on-demand slot for everything the correctness gate
+ * (`vitest.config.ts`, the config a bare `vitest run` picks up) excludes:
+ * wall-clock/scale benchmarks and the two tests whose outcome depends on
+ * the host machine or network rather than the code. See CONTRIBUTING.md's
+ * "Test gate" section and the exclude list in `vitest.config.ts` (root) for
+ * why each file lives here instead of the gate.
+ *
+ * `include` names this set explicitly — it is the mirror image of the
+ * root config's exclude list, not an independent glob, so the two stay in
+ * sync by inspection. Longer timeouts than the gate's 120s/60s: one case in
+ * tests/critical-performance-benchmark.test.ts measures ~128s of real work.
+ */
+export default defineConfig({
+  test: {
+    globals: true,
+    setupFiles: ['./tests/setup.ts'],
+    environment: 'node',
+
+    // Sequential, single fork — same isolation the gate uses, so a perf
+    // measurement isn't skewed by sibling test contention.
+    pool: 'forks',
+    poolOptions: {
+      forks: {
+        maxForks: 1,
+        minForks: 1,
+        singleFork: true,
+        isolate: true
+      }
+    },
+
+    testTimeout: 300000, // 5 minutes per test (the 128s case plus headroom)
+    hookTimeout: 120000,
+    teardownTimeout: 10000,
+
+    maxConcurrency: 1,
+    fileParallelism: false,
+
+    include: [
+      'tests/performance/**/*.{test,spec}.{js,ts}',
+      'tests/critical-performance-benchmark.test.ts',
+      'tests/api/performance-benchmarks.test.ts',
+      'tests/package-size-limit.test.ts',
+      'tests/model-loading.test.ts'
+    ],
+
+    reporters: process.env.CI ? ['dot'] : ['basic'],
+
+    retry: process.env.CI ? 1 : 0,
+    shard: process.env.VITEST_SHARD
+  }
+})