chore: Add .gitignore

Exclude development screenshots, Python cache, IDE files,
and old script versions from version control.

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

.gitignore

@@ -0,0 +1,26 @@
+# Screenshots de desarrollo
+*.png
+!images/*.png
+
+# Backups
+*.bak
+*.backup
+*~
+
+# Python
+__pycache__/
+*.pyc
+*.pyo
+
+# IDE
+.idea/
+.vscode/
+*.swp
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Versiones antiguas de scripts
+generate_assets.py
+generate_assets_v2.py