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)

.uv

@@ -5,17 +5,11 @@ keep-lockfile = true
 # Cache compiled bytecode for dependencies
 compile-bytecode = true
 
-# Use a local cache directory
-local-cache = true
-
 # Verbosity of output
 verbosity = "minimal"
 
-# Define which part of the environment to check
-environment-checks = ["python", "dependencies"]
+; # Define which part of the environment to check
+; environment-checks = ["python", "dependencies"]
 
 # How to resolve dependencies not specified with exact versions
 dependency-resolution = "strict"
-
-# If the cache and target directories are on different filesystems, hardlinking may not be supported.
-link-mode = "copy"