fix: TypeScript build errors (TS6 enum → const, MUI v9 sx props, theme)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/services/aiService.ts

@@ -15,7 +15,7 @@ export interface AIServiceProvider {
 }
 
 const MockupAIServiceProvider: AIServiceProvider = {
-  async extractCriteria(input: string): Promise<CriteriaExtractionResult> {
+  async extractCriteria(_input: string): Promise<CriteriaExtractionResult> {
     // Deterministic mock extraction — simulates AI parsing
     return {
       extractedCriteria: {