feat(proxy): add thinking signature rectifier for Claude API (#595)

* feat(proxy): add thinking signature rectifier for Claude API

Add automatic request rectification when Anthropic API returns signature
validation errors. This improves compatibility when switching between
different Claude providers or when historical messages contain incompatible
thinking block signatures.

- Add thinking_rectifier.rs module with trigger detection and rectification
- Integrate rectifier into forwarder error handling flow
- Remove thinking/redacted_thinking blocks and signature fields on retry
- Delete top-level thinking field when assistant message lacks thinking prefix

* fix(proxy): complete rectifier retry path with failover switch and chain continuation

- Add failover switch trigger on rectifier retry success when provider differs from start
- Replace direct error return with error categorization on rectifier retry failure
- Continue failover chain for retryable errors instead of terminating early

* feat(proxy): add rectifier config with master switch

- Add RectifierConfig struct with enabled and requestThinkingSignature fields
- Update should_rectify_thinking_signature to check master switch first
- Add tests for master switch functionality

* feat(db): add rectifier config storage in settings table

Store rectifier config as JSON in single key for extensibility

* feat(commands): add get/set rectifier config commands

* feat(ui): add rectifier config panel in advanced settings

- Add RectifierConfigPanel component with master switch and thinking signature toggle
- Add API wrapper for rectifier config
- Add i18n translations for zh/en/ja

* feat(proxy): integrate rectifier config into request forwarding

- Load rectifier config from database in RequestContext
- Pass config to RequestForwarder for runtime checking
- Use should_rectify_thinking_signature with config parameter

* test(proxy): add nested JSON error detection test for thinking rectifier

* fix(proxy): resolve HalfOpen permit leak and RectifierConfig default values

- Fix RectifierConfig::default() to return enabled=true (was false due to derive)
- Add release_permit_neutral() for releasing permits without affecting health stats
- Fix 3 permit leak points in rectifier retry branches
- Add unit tests for default values and permit release

* style(ui): format ProviderCard style attribute

* fix(rectifier): add detection for signature field required error

Add support for detecting "signature: Field required" error pattern
in the thinking signature rectifier. This enables automatic request
rectification when upstream API returns this specific validation error.

src/components/providers/ProviderCard.tsx

@@ -301,7 +301,11 @@ export function ProviderCard({
 
         <div
           className="relative flex items-center ml-auto min-w-0 gap-3"
-          style={{ "--actions-width": `${actionsWidth || 320}px` } as React.CSSProperties}
+          style={
+            {
+              "--actions-width": `${actionsWidth || 320}px`,
+            } as React.CSSProperties
+          }
         >
           {/* 用量信息区域 - hover 时向左移动，为操作按钮腾出空间 */}
           <div className="ml-auto">

src/components/settings/RectifierConfigPanel.tsx

@@ -0,0 +1,75 @@
+import { useEffect, useState } from "react";
+import { useTranslation } from "react-i18next";
+import { toast } from "sonner";
+import { Switch } from "@/components/ui/switch";
+import { Label } from "@/components/ui/label";
+import { settingsApi, type RectifierConfig } from "@/lib/api/settings";
+
+export function RectifierConfigPanel() {
+  const { t } = useTranslation();
+  const [config, setConfig] = useState<RectifierConfig>({
+    enabled: true,
+    requestThinkingSignature: true,
+  });
+  const [isLoading, setIsLoading] = useState(true);
+
+  useEffect(() => {
+    settingsApi
+      .getRectifierConfig()
+      .then(setConfig)
+      .catch((e) => console.error("Failed to load rectifier config:", e))
+      .finally(() => setIsLoading(false));
+  }, []);
+
+  const handleChange = async (updates: Partial<RectifierConfig>) => {
+    const newConfig = { ...config, ...updates };
+    setConfig(newConfig);
+    try {
+      await settingsApi.setRectifierConfig(newConfig);
+    } catch (e) {
+      console.error("Failed to save rectifier config:", e);
+      toast.error(String(e));
+      setConfig(config);
+    }
+  };
+
+  if (isLoading) return null;
+
+  return (
+    <div className="space-y-6">
+      <div className="flex items-center justify-between">
+        <div className="space-y-0.5">
+          <Label>{t("settings.advanced.rectifier.enabled")}</Label>
+          <p className="text-xs text-muted-foreground">
+            {t("settings.advanced.rectifier.enabledDescription")}
+          </p>
+        </div>
+        <Switch
+          checked={config.enabled}
+          onCheckedChange={(checked) => handleChange({ enabled: checked })}
+        />
+      </div>
+
+      <div className="space-y-4">
+        <h4 className="text-sm font-medium text-muted-foreground">
+          {t("settings.advanced.rectifier.requestGroup")}
+        </h4>
+        <div className="flex items-center justify-between pl-4">
+          <div className="space-y-0.5">
+            <Label>{t("settings.advanced.rectifier.thinkingSignature")}</Label>
+            <p className="text-xs text-muted-foreground">
+              {t("settings.advanced.rectifier.thinkingSignatureDescription")}
+            </p>
+          </div>
+          <Switch
+            checked={config.requestThinkingSignature}
+            disabled={!config.enabled}
+            onCheckedChange={(checked) =>
+              handleChange({ requestThinkingSignature: checked })
+            }
+          />
+        </div>
+      </div>
+    </div>
+  );
+}

src/components/settings/SettingsPage.tsx

@@ -9,6 +9,7 @@ import {
   Database,
   Server,
   ChevronDown,
+  Zap,
   Globe,
 } from "lucide-react";
 import * as AccordionPrimitive from "@radix-ui/react-accordion";
@@ -42,6 +43,7 @@ import { ModelTestConfigPanel } from "@/components/usage/ModelTestConfigPanel";
 import { AutoFailoverConfigPanel } from "@/components/proxy/AutoFailoverConfigPanel";
 import { FailoverQueueManager } from "@/components/proxy/FailoverQueueManager";
 import { UsageDashboard } from "@/components/usage/UsageDashboard";
+import { RectifierConfigPanel } from "@/components/settings/RectifierConfigPanel";
 import { useSettings } from "@/hooks/useSettings";
 import { useImportExport } from "@/hooks/useImportExport";
 import { useTranslation } from "react-i18next";
@@ -550,6 +552,28 @@ export function SettingsPage({
                         />
                       </AccordionContent>
                     </AccordionItem>
+
+                    <AccordionItem
+                      value="rectifier"
+                      className="rounded-xl glass-card overflow-hidden"
+                    >
+                      <AccordionTrigger className="px-6 py-4 hover:no-underline hover:bg-muted/50 data-[state=open]:bg-muted/50">
+                        <div className="flex items-center gap-3">
+                          <Zap className="h-5 w-5 text-purple-500" />
+                          <div className="text-left">
+                            <h3 className="text-base font-semibold">
+                              {t("settings.advanced.rectifier.title")}
+                            </h3>
+                            <p className="text-sm text-muted-foreground font-normal">
+                              {t("settings.advanced.rectifier.description")}
+                            </p>
+                          </div>
+                        </div>
+                      </AccordionTrigger>
+                      <AccordionContent className="px-6 pb-6 pt-4 border-t border-border/50">
+                        <RectifierConfigPanel />
+                      </AccordionContent>
+                    </AccordionItem>
                   </Accordion>
 
                   <div className="pt-4">

src/i18n/locales/en.json

@@ -190,6 +190,16 @@
       "data": {
         "title": "Data Management",
         "description": "Import/export configurations and backup/restore"
+      },
+      "rectifier": {
+        "title": "Rectifier",
+        "description": "Automatically fix API request compatibility issues",
+        "enabled": "Enable Rectifier",
+        "enabledDescription": "Master switch, all rectification features will be disabled when turned off",
+        "requestGroup": "Request Rectification",
+        "responseGroup": "Response Rectification",
+        "thinkingSignature": "Thinking Signature Rectification",
+        "thinkingSignatureDescription": "Automatically fix Claude API errors caused by thinking signature validation failures"
       }
     },
     "language": "Language",

src/i18n/locales/ja.json

@@ -190,6 +190,16 @@
       "data": {
         "title": "データ管理",
         "description": "設定のインポート/エクスポートとバックアップ/復元"
+      },
+      "rectifier": {
+        "title": "整流器",
+        "description": "API リクエストの互換性問題を自動修正",
+        "enabled": "整流器を有効化",
+        "enabledDescription": "マスタースイッチ、オフにするとすべての整流機能が無効になります",
+        "requestGroup": "リクエスト整流",
+        "responseGroup": "レスポンス整流",
+        "thinkingSignature": "Thinking 署名整流",
+        "thinkingSignatureDescription": "Claude API の thinking 署名検証エラーを自動修正"
       }
     },
     "language": "言語",

src/i18n/locales/zh.json

@@ -190,6 +190,16 @@
       "data": {
         "title": "数据管理",
         "description": "导入导出配置与备份恢复"
+      },
+      "rectifier": {
+        "title": "整流器",
+        "description": "自动修复 API 请求中的兼容性问题",
+        "enabled": "启用整流器",
+        "enabledDescription": "总开关，关闭后所有整流功能将被禁用",
+        "requestGroup": "请求整流",
+        "responseGroup": "响应整流",
+        "thinkingSignature": "Thinking 签名整流",
+        "thinkingSignatureDescription": "自动修复 Claude API 中因 thinking 签名校验失败导致的请求错误"
       }
     },
     "language": "界面语言",

src/lib/api/settings.ts

@@ -134,4 +134,17 @@ export const settingsApi = {
   > {
     return await invoke("get_tool_versions");
   },
+
+  async getRectifierConfig(): Promise<RectifierConfig> {
+    return await invoke("get_rectifier_config");
+  },
+
+  async setRectifierConfig(config: RectifierConfig): Promise<boolean> {
+    return await invoke("set_rectifier_config", { config });
+  },
 };
+
+export interface RectifierConfig {
+  enabled: boolean;
+  requestThinkingSignature: boolean;
+}