fix: resolve CI OOM by fixing bloated package-lock.json

The package-lock.json was incorrectly regenerated with 1170 entries
instead of 452 (2.5x bloat) when cross-spawn was added to root.
This caused npm install to run out of memory on GitHub Actions.

- Remove unnecessary cross-spawn from root package.json
- Restore package-lock.json to proper workspace structure
- Remove NODE_OPTIONS workaround from workflow files

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.github/workflows/test.yml

@@ -32,10 +32,7 @@ jobs:
       - name: Install dependencies
         # Use npm install instead of npm ci to correctly resolve platform-specific
         # optional dependencies (e.g., @tailwindcss/oxide, lightningcss binaries)
-        # Increase Node memory limit to prevent OOM during install
-        run: npm install --prefer-offline
-        env:
-          NODE_OPTIONS: --max_old_space_size=6144
+        run: npm install
 
       - name: Install Linux native bindings
         # Workaround for npm optional dependencies bug (npm/cli#4828)