feat: add comprehensive Sorbet type annotations with ActiveSupport::Concern support

- Add sorbet-runtime dependency to gemspec
- Add comprehensive type annotations to Configuration class
- Create RBI file with mixes_in_class_methods for proper class method typing
- Add ActiveSupport::Concern shim to handle included and class_methods DSL
- Add parameter validation for edge cases when RBI bypasses runtime checks
- Update tests to expect correct error messages from manual validation
- All 26 tests passing with full type safety
- Sorbet type checker passes with no errors

This implements the ActiveSupport::Concern DSL generator approach from
https://github.com/Shopify/tapioca/pull/360 to properly handle Sorbet
type checking with ActiveSupport::Concern modules.

lefthook.yml

@@ -45,13 +45,11 @@ pre-commit:
 
     json-lint:
       glob: "*.json"
+      exclude: |
+        .devcontainer/devcontainer.json
+        .vscode/settings.json
       run: |
         for file in {staged_files}; do
-          # Skip devcontainer.json files which use JSONC format
-          if [ "$(echo "$file" | grep -c 'devcontainer.json')" -gt 0 ] || [ "$(echo "$file" | grep -c '.vscode')" -gt 0 ]; then
-            echo "Skipping JSONC file: $file"
-            continue
-          fi
           echo "Checking $file"
           ruby -e "require 'json'; JSON.parse(File.read('$file'))" || exit 1
         done