Create a structure for different diff strategies, starting with unified (#55)

src/core/diff/DiffStrategy.ts

@@ -0,0 +1,16 @@
+import type { DiffStrategy } from './types'
+import { UnifiedDiffStrategy } from './strategies/unified'
+
+/**
+ * Get the appropriate diff strategy for the given model
+ * @param model The name of the model being used (e.g., 'gpt-4', 'claude-3-opus')
+ * @returns The appropriate diff strategy for the model
+ */
+export function getDiffStrategy(model: string): DiffStrategy {
+    // For now, return UnifiedDiffStrategy for all models
+    // This architecture allows for future optimizations based on model capabilities
+    return new UnifiedDiffStrategy()
+}
+
+export type { DiffStrategy }
+export { UnifiedDiffStrategy }