兼容人味文案空证据输出

src/lib/domain/__tests__/validation.test.ts

@@ -122,6 +122,24 @@ describe("domain validation", () => {
     expect(parsed.ai_taste_checks[0]?.rule_id).toBe("promotion_tone");
   });
 
+  it("normalizes empty AI taste check evidence from LLM copy results", () => {
+    const parsed = copyOptimizationResultSchema.parse({
+      optimized_text: "我把句子顺了一下。",
+      change_notes: [],
+      ai_taste_checks: [
+        {
+          rule_id: "promotion_tone",
+          status: "pass",
+          evidence: "",
+          suggestion: "",
+        },
+      ],
+      warnings: [],
+    });
+
+    expect(parsed.ai_taste_checks[0]?.evidence).toBe("未提供具体证据。");
+  });
+
   it("accepts an unconfirmed optimization fact card with unresolved items", () => {
     const parsed = optimizationFactCardSchema.parse({
       company_full_name: "",