chore(turbo): add src as global dependency for cache invalidation

The desktop app imports from the root src directory, but turbo wasn't
tracking those files for cache hash calculation. This caused CI builds
to use stale hashes when types changed in the root src directory.

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

turbo.json

@@ -1,5 +1,6 @@
 {
   "$schema": "https://turbo.build/schema.json",
+  "globalDependencies": ["src/**"],
   "tasks": {
     "build": {
       "dependsOn": ["^build"],