fix: set devtools build to --parallel=1 for stability

Reduce parallel build workers in devtools workflow to prevent
race conditions and improve build reliability.

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

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

Author: ScriptedAlchemy

.github/workflows/devtools.yml

@@ -53,10 +53,10 @@ jobs:
         run: npx cypress install
 
       - name: Warm Nx Cache
-        run: npx nx run-many --targets=build --projects=tag:type:pkg --parallel=4 --skip-nx-cache
+        run: npx nx run-many --targets=build --projects=tag:type:pkg --parallel=1 --skip-nx-cache
 
       - name: Run Affected Build
-        run: npx nx run-many --targets=build --projects=tag:type:pkg --parallel=4 --skip-nx-cache
+        run: npx nx run-many --targets=build --projects=tag:type:pkg --parallel=1 --skip-nx-cache
 
       - name: Configuration xvfb
         shell: bash