feat(admin): support user profile editing, password resetting, and email column with search

- Add UpdateUser API and logics supporting nickname, email, admin flag modification, and password reset.
- Relocate user delete button and confirmation Alert into the EditUserModal.
- Optimize admin Switch change to trigger instant API request with rollback support.
- Fix missing email field in edit form initialization by fetching full profile metadata.
- Render email column in users list and support email-based filtering in UserFilterBar.
- Remove hardcoded styles and sizes from Switch components to follow global theme.

frontend/app/globals.css

@@ -7,8 +7,8 @@
 @theme inline {
   --color-background: var(--background);
   --color-foreground: var(--foreground);
-  --font-sans: var(--font-geist-sans), system-ui, -apple-system, BlinkMacSystemFont, var(--font-noto-sans-sc), sans-serif;
-  --font-mono: var(--font-geist-mono), 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', var(--font-noto-sans-sc), monospace;
+  --font-sans: var(--font-inter), 'PingFang SC', 'Microsoft YaHei', sans-serif;
+  --font-mono: var(--font-geist-mono), 'SF Mono', 'Monaco', 'Inconsolata', 'Roboto Mono', 'PingFang SC', 'Microsoft YaHei', monospace;
   --color-sidebar-ring: var(--sidebar-ring);
   --color-sidebar-border: var(--sidebar-border);
   --color-sidebar-accent-foreground: var(--sidebar-accent-foreground);
@@ -196,4 +196,4 @@
     80% { transform: rotate(-1deg); }
     100% { transform: rotate(0deg); }
   }
-}
+}