perf(LLM任务): 首查短超时快速失败 + 退避抖动 + 标题失败跳过外观识别

生产 24h 数据：外观专利任务 LLM 重试失败 93+82 次几乎全是超时，
终态 41 行降级为「外观识别异常」；成功调用 p99=34s、超 60s 仅 0.02%。
原策略每轮重试都挂满 90s（被全局 call-timeout 钳制），且 1.5s/3s
密集重试整批落在同一劣化窗口内。

- 第 1 次尝试改用 llm-first-attempt-read-timeout-millis（默认 60s）快速失败，
  重试走完整读超时，慢而成功的正常调用不被误杀
- 重试等待改 LlmRetryBackoff：2s/10s + ±30% 抖动，覆盖更长窗口并打散同批尖峰
- 外观专利标题识别失败时跳过外观请求（该行必走回退，外观结果本就会被丢弃）

backend-java/src/test/java/com/nanri/aiimage/common/retry/LlmRetryBackoffTest.java

@@ -0,0 +1,47 @@
+package com.nanri.aiimage.common.retry;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/** 重试退避策略：档位、上下界与抖动范围（固定 random 消除随机性）。 */
+class LlmRetryBackoffTest {
+
+    @Test
+    void firstRetryWaitsTwoSeconds() {
+        assertThat(LlmRetryBackoff.delayMillis(1, 0.5d)).isEqualTo(2_000L);
+    }
+
+    @Test
+    void secondRetryWaitsTenSeconds() {
+        assertThat(LlmRetryBackoff.delayMillis(2, 0.5d)).isEqualTo(10_000L);
+    }
+
+    @Test
+    void attemptsBeyondTableUseLastTier() {
+        assertThat(LlmRetryBackoff.delayMillis(3, 0.5d)).isEqualTo(10_000L);
+        assertThat(LlmRetryBackoff.delayMillis(9, 0.5d)).isEqualTo(10_000L);
+    }
+
+    @Test
+    void jitterStaysWithinThirtyPercent() {
+        assertThat(LlmRetryBackoff.delayMillis(1, 0d)).isEqualTo(1_400L);
+        assertThat(LlmRetryBackoff.delayMillis(1, 1d)).isEqualTo(2_600L);
+        assertThat(LlmRetryBackoff.delayMillis(2, 0d)).isEqualTo(7_000L);
+        assertThat(LlmRetryBackoff.delayMillis(2, 1d)).isEqualTo(13_000L);
+    }
+
+    @Test
+    void attemptIndexBelowOneIsClampedToFirstTier() {
+        assertThat(LlmRetryBackoff.delayMillis(0, 0.5d)).isEqualTo(2_000L);
+        assertThat(LlmRetryBackoff.delayMillis(-3, 0.5d)).isEqualTo(2_000L);
+    }
+
+    @Test
+    void randomDelayAlwaysPositiveAndBounded() {
+        for (int i = 0; i < 200; i++) {
+            long delay = LlmRetryBackoff.delayMillis(1);
+            assertThat(delay).isBetween(1_400L, 2_600L);
+        }
+    }
+}

backend-java/src/test/java/com/nanri/aiimage/modules/appearancepatent/client/AppearancePatentLlmClientHttpTest.java

@@ -31,6 +31,10 @@ class AppearancePatentLlmClientHttpTest {
     private final ObjectMapper objectMapper = new ObjectMapper();
     private final Map<String, AtomicInteger> callCounts = new ConcurrentHashMap<>();
     private final List<String> capturedBodies = new ArrayList<>();
+    /** 纯文本（标题提取）请求计数：用于验证重试次数与「跳过外观」行为。 */
+    private final AtomicInteger textRequestCount = new AtomicInteger();
+    private volatile boolean failTextRequests = false;
+    private volatile long firstTextRequestDelayMillis = 0L;
 
     private AppearancePatentLlmClient client;
 
@@ -60,6 +64,16 @@ class AppearancePatentLlmClientHttpTest {
     private void handleChat(HttpExchange exchange) throws IOException {
         String body = new String(exchange.getRequestBody().readAllBytes(), StandardCharsets.UTF_8);
         capturedBodies.add(body);
+        if (!body.contains("\"type\":\"image_url\"")) {
+            int sequence = textRequestCount.incrementAndGet();
+            if (sequence == 1 && firstTextRequestDelayMillis > 0L) {
+                sleep(firstTextRequestDelayMillis);
+            }
+            if (failTextRequests) {
+                respond(exchange, 502, "{\"error\":{\"message\":\"bad gateway\"}}");
+                return;
+            }
+        }
         try {
             @SuppressWarnings("unchecked")
             Map<String, Object> request = objectMapper.readValue(body, Map.class);
@@ -103,6 +117,32 @@ class AppearancePatentLlmClientHttpTest {
         }
     }
 
+    private void respond(HttpExchange exchange, int status, String body) throws IOException {
+        byte[] bytes = body.getBytes(StandardCharsets.UTF_8);
+        exchange.getResponseHeaders().set("Content-Type", "application/json; charset=utf-8");
+        exchange.sendResponseHeaders(status, bytes.length);
+        try (OutputStream os = exchange.getResponseBody()) {
+            os.write(bytes);
+        }
+    }
+
+    private void sleep(long millis) {
+        try {
+            Thread.sleep(millis);
+        } catch (InterruptedException interruptedException) {
+            Thread.currentThread().interrupt();
+        }
+    }
+
+    /** 用自定义超时/重试参数构建客户端（setUp 里的 client 用属性默认值）。 */
+    private AppearancePatentLlmClient buildClient(java.util.function.Consumer<AppearancePatentProperties> customizer) {
+        AppearancePatentProperties properties = new AppearancePatentProperties();
+        properties.setLlmHost("http://127.0.0.1:" + server.getAddress().getPort());
+        customizer.accept(properties);
+        return new AppearancePatentLlmClient(properties, objectMapper, null,
+                new BrandCheckClient(new BrandCheckProperties(), null), mock(UserSecretUsageService.class));
+    }
+
     private boolean messagesBodyContains(HttpExchange exchange, String text) {
         return capturedBodies.stream().anyMatch(b -> b.contains(text));
     }
@@ -194,4 +234,43 @@ class AppearancePatentLlmClientHttpTest {
         assertThat(appearanceBody).contains("\"type\":\"json_object\"");
         assertThat(appearanceBody).contains("产品描述：普通数据线");
     }
+
+    /** 标题识别失败 → 本行必走回退（外观结果会被丢弃），外观请求不再发出：劣化窗口下少一轮无效重试。 */
+    @Test
+    void titleFailureSkipsAppearanceCallAndKeepsFallback() {
+        failTextRequests = true;
+        AppearancePatentLlmClient singleAttemptClient = buildClient(p -> {
+            p.setLlmRetryTimes(1);
+            p.setLlmFirstAttemptReadTimeoutMillis(5_000);
+            p.setLlmReadTimeoutMillis(5_000);
+        });
+
+        List<AppearancePatentResultRowDto> rows = singleAttemptClient.inspectRows(
+                List.of(row("7", "B007", "任意标题", "", "https://img.example.com/7.jpg")), null, "test-key");
+
+        assertThat(rows.get(0).getAppearanceRisk()).isEqualTo("外观识别异常");
+        assertThat(capturedBodies).noneMatch(b -> b.contains("\"type\":\"image_url\""));
+        assertThat(textRequestCount.get()).isEqualTo(1);
+    }
+
+    /** 首查用更短超时快速失败、重试走完整超时并成功（上游偶发单请求不响应的兜底路径）。 */
+    @Test
+    void firstAttemptTimeoutRetriesWithFullBudgetAndSucceeds() {
+        firstTextRequestDelayMillis = 1_200L;
+        AppearancePatentLlmClient twoAttemptClient = buildClient(p -> {
+            p.setLlmRetryTimes(2);
+            p.setLlmFirstAttemptReadTimeoutMillis(400);
+            p.setLlmReadTimeoutMillis(8_000);
+        });
+
+        long startedAt = System.nanoTime();
+        List<AppearancePatentResultRowDto> rows = twoAttemptClient.inspectRows(
+                List.of(row("8", "B008", "普通数据线", "", "https://img.example.com/8.jpg")), null, "test-key");
+        long elapsedMs = (System.nanoTime() - startedAt) / 1_000_000;
+
+        AppearancePatentResultRowDto result = rows.get(0);
+        assertThat(result.getAppearanceRisk()).isEqualTo("无侵权");
+        assertThat(textRequestCount.get()).isEqualTo(2);
+        assertThat(elapsedMs).isGreaterThanOrEqualTo(400L);
+    }
 }