feat: add dependency direction enforcement (v0.4.0)

Implement dependency direction detection to enforce Clean Architecture rules:
- Domain layer can only import from Domain and Shared
- Application layer can only import from Domain, Application, and Shared
- Infrastructure layer can import from all layers
- Shared layer can be imported by all layers

Added:
- IDependencyDirectionDetector interface in domain layer
- DependencyViolation value object with detailed suggestions and examples
- DependencyDirectionDetector implementation in infrastructure
- Integration with AnalyzeProject use case
- New DEPENDENCY_DIRECTION rule in constants
- 43 comprehensive tests covering all scenarios (100% passing)
- Good and bad examples in examples directory

Improvements:
- Optimized extractLayerFromImport method to reduce complexity
- Fixed indentation in DependencyGraph.ts
- Updated getExampleFix to avoid false positives in old detector

Test Results:
- All 261 tests passing
- Build successful
- Self-check: 0 architecture violations in src code

packages/guardian/src/domain/services/IDependencyDirectionDetector.ts

@@ -0,0 +1,47 @@
+import { DependencyViolation } from "../value-objects/DependencyViolation"
+
+/**
+ * Interface for detecting dependency direction violations in the codebase
+ *
+ * Dependency direction violations occur when a layer imports from a layer
+ * that it should not depend on according to Clean Architecture principles:
+ * - Domain should not import from Application or Infrastructure
+ * - Application should not import from Infrastructure
+ * - Infrastructure can import from Application and Domain
+ * - Shared can be imported by all layers
+ */
+export interface IDependencyDirectionDetector {
+    /**
+     * Detects dependency direction violations in the given code
+     *
+     * Analyzes import statements to identify violations of dependency rules
+     * between architectural layers.
+     *
+     * @param code - Source code to analyze
+     * @param filePath - Path to the file being analyzed
+     * @param layer - The architectural layer of the file (domain, application, infrastructure, shared)
+     * @returns Array of detected dependency direction violations
+     */
+    detectViolations(
+        code: string,
+        filePath: string,
+        layer: string | undefined,
+    ): DependencyViolation[]
+
+    /**
+     * Checks if an import violates dependency direction rules
+     *
+     * @param fromLayer - The layer that is importing
+     * @param toLayer - The layer being imported
+     * @returns True if the import violates dependency rules
+     */
+    isViolation(fromLayer: string, toLayer: string): boolean
+
+    /**
+     * Extracts the layer from an import path
+     *
+     * @param importPath - The import path to analyze
+     * @returns The layer name if detected, undefined otherwise
+     */
+    extractLayerFromImport(importPath: string): string | undefined
+}