chore: update env example and gitignore, add implementation plan

- Update .env.example with documentation and default values
- Add .resources to gitignore (dummy test files)
- Add APK parsing fix implementation plan document

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitignore

@@ -40,3 +40,6 @@ yarn-error.log*
 *.tsbuildinfo
 next-env.d.ts
 .env
+
+# dumy files for download tests
+.resources