feat: 媒体库 blob 去重存储与品牌/注册等前端调整

新增：
- blob_store 二进制去重存储 + blob_dedup 测试

其它：
- 后端 settings/auth/media_library/upload/operations 服务与 handler 调整
- 前端品牌（BrandLockup/BrandCropModal/BrandSeoPanel）、注册、媒体库、分析详情页、Header/SiteChrome 等更新

frontend/app/admin/settings/BasicIdentityPanel.tsx

@@ -2,7 +2,7 @@
 
 import { X } from "lucide-react";
 import { useEffect, useRef, useState } from "react";
-import { AdminField, AdminSettingsActions, AdminSettingsGroup } from "@/components/admin";
+import { AdminField, AdminSettingsActions, AdminSettingsGroup, AdminSwitch } from "@/components/admin";
 import { apiUpdateSiteSettings, apiOperations, type PublicSettings } from "@/lib/api";
 import { BRAND_LIMITS, runeCount, siteDocumentTitle } from "@/lib/brand";
 import { toast } from "@/lib/toast";
@@ -25,6 +25,7 @@ export default function BasicIdentityPanel({
   }, []);
   const [wordmark, setWordmark] = useState(initial.site_wordmark);
   const [slogan, setSlogan] = useState(initial.site_slogan);
+  const [sloganVisible, setSloganVisible] = useState(initial.brand_slogan_visible);
   const [desc, setDesc] = useState(initial.site_description);
   const [keywords, setKeywords] = useState<string[]>(initial.site_keywords);
   const [kwInput, setKwInput] = useState("");
@@ -32,6 +33,7 @@ export default function BasicIdentityPanel({
     name: initial.site_name,
     wordmark: initial.site_wordmark,
     slogan: initial.site_slogan,
+    sloganVisible: initial.brand_slogan_visible,
     desc: initial.site_description,
     keywords: initial.site_keywords,
   });
@@ -44,6 +46,7 @@ export default function BasicIdentityPanel({
     name.trim() !== saved.name ||
     wordmark.trim() !== saved.wordmark ||
     slogan.trim() !== saved.slogan ||
+    sloganVisible !== saved.sloganVisible ||
     desc.trim() !== saved.desc ||
     JSON.stringify(keywords) !== JSON.stringify(saved.keywords);
 
@@ -85,6 +88,7 @@ export default function BasicIdentityPanel({
     setName(saved.name);
     setWordmark(saved.wordmark);
     setSlogan(saved.slogan);
+    setSloganVisible(saved.sloganVisible);
     setDesc(saved.desc);
     setKeywords([...saved.keywords]);
     setKwInput("");
@@ -98,6 +102,7 @@ export default function BasicIdentityPanel({
       name: name.trim(),
       wordmark: wordmark.trim(),
       slogan: slogan.trim(),
+      sloganVisible,
       desc: desc.trim(),
       keywords: [...keywords],
     };
@@ -115,6 +120,7 @@ export default function BasicIdentityPanel({
         site_name: snap.name,
         site_wordmark: snap.wordmark,
         site_slogan: snap.slogan,
+        brand_slogan_visible: snap.sloganVisible,
         site_description: snap.desc,
         site_keywords: snap.keywords,
       });
@@ -123,12 +129,14 @@ export default function BasicIdentityPanel({
         name: res.site_name,
         wordmark: res.site_wordmark,
         slogan: res.site_slogan,
+        sloganVisible: res.brand_slogan_visible,
         desc: res.site_description,
         keywords: res.site_keywords,
       });
       setName((v) => (v.trim() === snap.name ? res.site_name : v));
       setWordmark((v) => (v.trim() === snap.wordmark ? res.site_wordmark : v));
       setSlogan((v) => (v.trim() === snap.slogan ? res.site_slogan : v));
+      setSloganVisible((v) => (v === snap.sloganVisible ? res.brand_slogan_visible : v));
       setDesc((v) => (v.trim() === snap.desc ? res.site_description : v));
       setKeywords((prev) =>
         JSON.stringify(prev) === JSON.stringify(snap.keywords) ? res.site_keywords : prev,
@@ -199,18 +207,49 @@ export default function BasicIdentityPanel({
           />
         </div>
 
-        <AdminField
-          id="site-slogan"
-          label="标语"
-          className="admin-identity-field"
-          maxLength={BRAND_LIMITS.slogan}
-          value={slogan}
-          onChange={(v) => {
-            setSlogan(v);
-            clearSaveError();
-          }}
-          placeholder="技术分享与讨论"
-        />
+        <div className="admin-identity-field">
+          <div className="admin-field-head">
+            <label className="field-label" htmlFor="site-slogan">
+              标语
+            </label>
+            <span className="admin-field-count" aria-hidden>
+              {slogan.length}/{BRAND_LIMITS.slogan}
+            </span>
+          </div>
+          <div
+            className="flex items-center gap-2 mb-2"
+            title={slogan.trim() ? "在页眉站名下方显示副标题" : "先填写标语后可开启"}
+          >
+            <AdminSwitch
+              checked={sloganVisible}
+              disabled={!slogan.trim()}
+              onChange={() => {
+                setSloganVisible((v) => !v);
+                clearSaveError();
+              }}
+              label="页眉显示标语"
+            />
+            <span
+              className="text-[12px]"
+              style={{ color: slogan.trim() ? "var(--ink-2)" : "var(--ink-3)" }}
+            >
+              页眉显示标语
+            </span>
+          </div>
+          <div className="admin-field-shell">
+            <input
+              id="site-slogan"
+              className="admin-field-input"
+              maxLength={BRAND_LIMITS.slogan}
+              value={slogan}
+              onChange={(e) => {
+                setSlogan(e.target.value);
+                clearSaveError();
+              }}
+              placeholder="技术分享与讨论"
+            />
+          </div>
+        </div>
         <p className="admin-identity-title-preview" aria-live="polite">
           浏览器标题预览 · <strong>{preview}</strong>
         </p>