fix(小宝预警): 稳定AI建议缓存签名

apps/web/lib/xiaobao-risk-ai.test.ts

@@ -7,6 +7,7 @@ import {
   buildRiskInterpretRequest,
   findLatestRiskInsightForVersion,
   findPreviousRiskSnapshot,
+  getReusableInsight,
   shouldRequestRiskInsight,
   shouldRequestRiskInsightWithCacheGate,
   shouldRequestRiskInsightWithCooldown,
@@ -328,6 +329,38 @@ test('buildRiskInsightSignature changes when trend direction delta or activity m
   assert.notEqual(base, changed);
 });
 
+test('buildRiskInsightSignature stays stable when only volatile same-day forecast timing changes', () => {
+  const base = buildRiskInsightSignature(risk({
+    forecastReleaseDate: '2026-07-14T03:06:58.211Z',
+    signals: { ...risk().signals, daysToExpectedRelease: 30.9 },
+  }));
+  const changed = buildRiskInsightSignature(risk({
+    forecastReleaseDate: '2026-07-14T03:37:15.903Z',
+    signals: { ...risk().signals, daysToExpectedRelease: 30.1 },
+  }));
+
+  assert.equal(base, changed);
+});
+
+test('getReusableInsight reuses legacy signatures with volatile forecast timestamps', () => {
+  const current = risk({
+    forecastReleaseDate: '2026-07-14T03:37:15.903Z',
+    signals: { ...risk().signals, daysToExpectedRelease: 30.1 },
+  });
+  const legacy = insight({
+    riskSignature: JSON.stringify({
+      ...JSON.parse(buildRiskInsightSignature(current)),
+      forecastReleaseDate: '2026-07-14T03:06:58.211Z',
+      signals: {
+        ...current.signals,
+        daysToExpectedRelease: 30.9,
+      },
+    }),
+  });
+
+  assert.equal(getReusableInsight([legacy], current)?.insight.summary, legacy.insight.summary);
+});
+
 test('buildRiskInterpretRequest compresses frontend risk evidence for the backend AI contract', () => {
   const payload = buildRiskInterpretRequest(risk());