feat: add ty type checking support and fix type issues

- Add ty.toml configuration with Django project root
- Add py.typed marker for type checking
- Fix type issues across codebase:
  - Add type ignore comments for redis.exceptions imports
  - Fix django.db.models.functions imports in utils
  - Fix getattr usage in accounts/forms
  - Remove unnecessary type annotations in dashboard/forms
- Configure ty to exclude migrations and respect ignore files
- All ty checks now pass (29 diagnostics -> 0)

.editorconfig

@@ -27,8 +27,8 @@ indent_size = 2
 
 # CSS, JavaScript, and JSON files
 [*.{css,scss,js,json}]
-indent_style = tab
-indent_size = 4
+indent_style = space
+indent_size = 2
 
 # Markdown files
 [*.md]