test: fix windows environment and cleanup issues

- Ensure 'SystemRoot', 'COMSPEC', 'windir', and 'PATHEXT' are passed to node-pty on Windows to prevent 'posix_spawnp' failures.
- Clean up test directories in 'TestRig.setup' to ensure a fresh state for retries and prevent telemetry log accumulation (fixing the 1, 2, 3 failure pattern).
- Fix path normalization in 'Hook Disabling' test to ensure disabled hooks are correctly matched on Windows.

Part of https://github.com/google-gemini/gemini-cli/pull/18665

integration-tests/hooks-system.test.ts

@@ -1831,7 +1831,7 @@ console.log(JSON.stringify({decision: "block", systemMessage: "Disabled hook sho
         settings: {
           hooksConfig: {
             enabled: true,
-            disabled: [`node "${disabledPath}"`], // Disable the second hook
+            disabled: [normalizePath(`node "${disabledPath}"`)], // Disable the second hook
           },
           hooks: {
             BeforeTool: [

packages/test-utils/src/test-rig.ts

@@ -367,6 +367,15 @@ export class TestRig {
       env['INTEGRATION_TEST_FILE_DIR'] || join(os.tmpdir(), 'gemini-cli-tests');
     this.testDir = join(testFileDir, sanitizedName);
     this.homeDir = join(testFileDir, sanitizedName + '-home');
+
+    // Clean up existing directories from previous runs (e.g. retries)
+    if (fs.existsSync(this.testDir)) {
+      fs.rmSync(this.testDir, { recursive: true, force: true });
+    }
+    if (fs.existsSync(this.homeDir)) {
+      fs.rmSync(this.homeDir, { recursive: true, force: true });
+    }
+
     mkdirSync(this.testDir, { recursive: true });
     mkdirSync(this.homeDir, { recursive: true });
     if (options.fakeResponsesPath) {
@@ -1308,6 +1317,15 @@ export class TestRig {
       envVars['PATH'] = process.env['PATH'];
     }
 
+    // Add critical Windows environment variables if missing
+    if (process.platform === 'win32') {
+      ['SystemRoot', 'COMSPEC', 'windir', 'PATHEXT'].forEach((key) => {
+        if (!envVars[key] && process.env[key]) {
+          envVars[key] = process.env[key];
+        }
+      });
+    }
+
     const ptyOptions: pty.IPtyForkOptions = {
       name: 'xterm-color',
       cols: 80,