fix(web): resolve login API 405 and logo 404 on /admin/ deployment

- .env.production: VUE_APP_BASE_API=api → /admin
  (auth.js URLs start with /api/, so baseURL=api caused axios to emit
   api/api/... → browser resolves to /admin/api/api/..., backend returns 405)
- Login.vue: <img src="/logo.png"> → src="logo.png" (relative,
  resolves correctly under /admin/ subpath)
- public/logo.png: added (copied from web/logo.png)
- .gitignore: add !cfc-web/public/logo.png exception

.gitignore

@@ -46,6 +46,7 @@ worktrees/
 !cfc-frontend/static/*.png
 *.png
 !docs/**/*.png
+!cfc-web/public/logo.png
 
 # Python
 *.py

cfc-web/.env.production

@@ -1,2 +1,2 @@
-VUE_APP_BASE_API=api
+VUE_APP_BASE_API=/admin
 VUE_APP_SKIP_CAPTCHA=true

cfc-web/.last_build_commit

@@ -1 +1 @@
-13667502b99b4dde1ba8c5f7a186cdcb3fe9806f
+1dfc4a2161b67b6b896fe6bb7d5fa6e60f135e79

cfc-web/src/views/Login.vue

@@ -6,7 +6,7 @@
 
         <!-- ===== Logo + 品牌标识 ===== -->
         <div class="brand-header">
-          <img src="/logo.png" alt="浠艾福" class="logo-img" />
+          <img src="logo.png" alt="浠艾福" class="logo-img" />
           <div class="brand-titles">
             <span class="brand-cn">亿图腾<span class="brand-dot">·</span>浠艾福</span>
             <span class="brand-en">Care Family</span>