chore: update docs

Author: V3RON

website/src/docs/getting-started/configuration.mdx

@@ -102,6 +102,7 @@ For Expo projects, the `entryPoint` should be set to the path specified in the `
 | `coverage`                         | Coverage configuration object.                                                |
 | `coverage.root`                    | Root directory for coverage instrumentation (default: `process.cwd()`).       |
 | `forwardClientLogs`                | Forward console logs from the app to the terminal (default: `false`).         |
+| `unstable__enableMetroCache`       | Enable Metro transformation cache under `.harness/metro-cache` and log when reusing it (default: `false`). |
 
 ## Test Runners
 

website/src/docs/guides/ci-cd.md

@@ -211,6 +211,22 @@ jobs:
           runner: ios
 ```
 
+## Metro cache (optional)
+
+React Native Harness can persist Metro's transformation cache under `.harness/metro-cache` in your project root. Enabling it in config (`unstable__enableMetroCache: true`) speeds up repeated Metro runs. In CI, you can cache this directory to avoid re-transforming unchanged files between workflow runs:
+
+```yaml
+- name: Metro cache
+  uses: actions/cache@v4
+  with:
+    path: .harness/metro-cache
+    key: ${{ runner.os }}-metro-cache-${{ hashFiles('**/pnpm-lock.yaml', '**/yarn.lock', '**/package-lock.json', '**/metro.config.js', '**/metro.config.mjs', '**/babel.config.js', '**/babel.config.mjs') }}
+    restore-keys: |
+      ${{ runner.os }}-metro-cache-
+```
+
+Use a key that includes your lockfile and Metro/Babel config paths so the cache invalidates when dependencies or bundler config change.
+
 ## Build Artifact Caching
 
 The workflow includes build artifact caching to significantly reduce CI execution times. When native modules haven't changed, you can reuse the same debug builds instead of rebuilding from scratch.