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/progress.go

@@ -2,14 +2,20 @@
 package internal
 
 import (
+	"fmt"
+
 	"github.com/schollz/progressbar/v3"
 )
 
 // ProgressBarManager handles progress bar creation and management.
+// It implements the ProgressManager interface.
 type ProgressBarManager struct {
 	quiet bool
 }
 
+// Compile-time interface check.
+var _ ProgressManager = (*ProgressBarManager)(nil)
+
 // NewProgressBarManager creates a new progress bar manager.
 func NewProgressBarManager(quiet bool) *ProgressBarManager {
 	return &ProgressBarManager{
@@ -48,3 +54,36 @@ func (pm *ProgressBarManager) FinishProgressBar(bar *progressbar.ProgressBar) {
 		_ = bar.Finish()
 	}
 }
+
+// FinishProgressBarWithNewline completes the progress bar display and adds a newline.
+func (pm *ProgressBarManager) FinishProgressBarWithNewline(bar *progressbar.ProgressBar) {
+	pm.FinishProgressBar(bar)
+	if bar != nil {
+		fmt.Println()
+	}
+}
+
+// ProcessWithProgressBar executes a function for each item with progress tracking.
+// The processFunc receives the item and the progress bar for updating.
+func (pm *ProgressBarManager) ProcessWithProgressBar(
+	description string,
+	items []string,
+	processFunc func(item string, bar *progressbar.ProgressBar),
+) {
+	bar := pm.CreateProgressBarForFiles(description, items)
+	defer pm.FinishProgressBarWithNewline(bar)
+
+	for _, item := range items {
+		processFunc(item, bar)
+		if bar != nil {
+			_ = bar.Add(1)
+		}
+	}
+}
+
+// UpdateProgressBar safely updates the progress bar if it exists.
+func (pm *ProgressBarManager) UpdateProgressBar(bar *progressbar.ProgressBar) {
+	if bar != nil {
+		_ = bar.Add(1)
+	}
+}