chore: import upstream snapshot with attribution

vitest.config.ts

@@ -0,0 +1,36 @@
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+  test: {
+    globals: true,
+    environment: 'node',
+    include: ['__tests__/**/*.test.ts'],
+    /**
+     * Several MCP integration tests (mcp-daemon, mcp-initialize, mcp-ppid-watchdog,
+     * mcp-roots) spawn `dist/bin/codegraph.js serve --mcp` with `process.execPath`
+     * and rely on the child inheriting `process.env`. On a Node >= 25 dev machine
+     * the CLI's hard-block (src/bin/codegraph.ts) would otherwise exit the child
+     * before it ever responds, so every spawn-based test times out — see #478.
+     *
+     * Setting the override here keeps the CLI's runtime guard intact for end
+     * users (it's still enforced when `codegraph` is invoked directly) while
+     * letting the test suite run on whatever Node the contributor happens to
+     * have installed. CI on Node 22/23 is unaffected — the guard doesn't fire
+     * there, so the variable is a no-op.
+     */
+    env: {
+      CODEGRAPH_ALLOW_UNSAFE_NODE: '1',
+      /**
+       * The suite spawns real CLI/MCP processes; without this they would write
+       * telemetry state into the contributor's real ~/.codegraph and count test
+       * tool calls as real usage. The telemetry unit tests are unaffected —
+       * they inject their own `env` via the Telemetry constructor.
+       */
+      CODEGRAPH_TELEMETRY: '0',
+    },
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'json', 'html'],
+    },
+  },
+});