refactor: major codebase improvements and test framework overhaul

This commit represents a comprehensive refactoring of the codebase focused on
improving code quality, testability, and maintainability.

Key improvements:
- Implement dependency injection and interface-based architecture
- Add comprehensive test framework with fixtures and test suites
- Fix all linting issues (errcheck, gosec, staticcheck, goconst, etc.)
- Achieve full EditorConfig compliance across all files
- Replace hardcoded test data with proper fixture files
- Add configuration loader with hierarchical config support
- Improve error handling with contextual information
- Add progress indicators for better user feedback
- Enhance Makefile with help system and improved editorconfig commands
- Consolidate constants and remove deprecated code
- Strengthen validation logic for GitHub Actions
- Add focused consumer interfaces for better separation of concerns

Testing improvements:
- Add comprehensive integration tests
- Implement test executor pattern for better test organization
- Create extensive YAML fixture library for testing
- Fix all failing tests and improve test coverage
- Add validation test fixtures to avoid embedded YAML in Go files

Build and tooling:
- Update Makefile to show help by default
- Fix editorconfig commands to use eclint properly
- Add comprehensive help documentation to all make targets
- Improve file selection patterns to avoid glob errors

This refactoring maintains backward compatibility while significantly
improving the internal architecture and developer experience.

internal/git/detector_test.go

@@ -20,14 +20,14 @@ func TestFindRepositoryRoot(t *testing.T) {
 			setupFunc: func(t *testing.T, tmpDir string) string {
 				// Create .git directory
 				gitDir := filepath.Join(tmpDir, ".git")
-				err := os.MkdirAll(gitDir, 0755)
+				err := os.MkdirAll(gitDir, 0750) // #nosec G301 -- test directory permissions
 				if err != nil {
 					t.Fatalf("failed to create .git directory: %v", err)
 				}
 
 				// Create subdirectory to test from
 				subDir := filepath.Join(tmpDir, "subdir", "nested")
-				err = os.MkdirAll(subDir, 0755)
+				err = os.MkdirAll(subDir, 0750) // #nosec G301 -- test directory permissions
 				if err != nil {
 					t.Fatalf("failed to create subdirectory: %v", err)
 				}
@@ -54,7 +54,7 @@ func TestFindRepositoryRoot(t *testing.T) {
 			setupFunc: func(t *testing.T, tmpDir string) string {
 				// Create subdirectory without .git
 				subDir := filepath.Join(tmpDir, "subdir")
-				err := os.MkdirAll(subDir, 0755)
+				err := os.MkdirAll(subDir, 0750) // #nosec G301 -- test directory permissions
 				if err != nil {
 					t.Fatalf("failed to create subdirectory: %v", err)
 				}
@@ -117,7 +117,7 @@ func TestDetectGitRepository(t *testing.T) {
 			setupFunc: func(t *testing.T, tmpDir string) string {
 				// Create .git directory
 				gitDir := filepath.Join(tmpDir, ".git")
-				err := os.MkdirAll(gitDir, 0755)
+				err := os.MkdirAll(gitDir, 0750) // #nosec G301 -- test directory permissions
 				if err != nil {
 					t.Fatalf("failed to create .git directory: %v", err)
 				}
@@ -150,7 +150,7 @@ func TestDetectGitRepository(t *testing.T) {
 			name: "SSH remote URL",
 			setupFunc: func(t *testing.T, tmpDir string) string {
 				gitDir := filepath.Join(tmpDir, ".git")
-				err := os.MkdirAll(gitDir, 0755)
+				err := os.MkdirAll(gitDir, 0750) // #nosec G301 -- test directory permissions
 				if err != nil {
 					t.Fatalf("failed to create .git directory: %v", err)
 				}
@@ -185,7 +185,7 @@ func TestDetectGitRepository(t *testing.T) {
 			name: "git repository without origin remote",
 			setupFunc: func(t *testing.T, tmpDir string) string {
 				gitDir := filepath.Join(tmpDir, ".git")
-				err := os.MkdirAll(gitDir, 0755)
+				err := os.MkdirAll(gitDir, 0750) // #nosec G301 -- test directory permissions
 				if err != nil {
 					t.Fatalf("failed to create .git directory: %v", err)
 				}