style(web): 全站 font-mono → font-body (DM Mono 設計系統套用)

45 個 component + 6 個 page 統一從舊 font-mono 遷移到
font-body (DM Mono)，確保設計系統一致性。

font-body = DM Mono (等寬)，視覺效果相同但走新設計 token。
保留: font-heading (Syne)、font-dot-matrix (VT323/DSEG7)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/components/ui/approval-modal.tsx

@@ -104,7 +104,7 @@ export function ApprovalModal({
               <h2 className="font-heading text-lg font-bold text-nothing-gray-900">
                 {displayTitle}
               </h2>
-              <p className="text-xs text-nothing-gray-500 font-mono">
+              <p className="text-xs text-nothing-gray-500 font-body">
                 Multi-Sig Authorization Required
               </p>
             </div>
@@ -127,7 +127,7 @@ export function ApprovalModal({
                 >
                   <ChevronLeft className="w-4 h-4" />
                 </button>
-                <span className="text-sm font-mono text-nothing-gray-600 tabular-nums min-w-[3rem] text-center">
+                <span className="text-sm font-body text-nothing-gray-600 tabular-nums min-w-[3rem] text-center">
                   {current} / {total}
                 </span>
                 <button

apps/web/src/components/ui/slide-panel.tsx

@@ -112,7 +112,7 @@ export function SlidePanel({
           {/* 導航控制 */}
           {(onPrev || onNext) && current && total && (
             <div className="flex items-center gap-2">
-              <span className="text-xs font-mono text-nothing-gray-400">
+              <span className="text-xs font-body text-nothing-gray-400">
                 {current} / {total}
               </span>
               <div className="flex items-center gap-1">

apps/web/src/components/ui/status-orb.tsx

@@ -242,7 +242,7 @@ export const StatusBadge = forwardRef<HTMLSpanElement, StatusBadgeProps>(
         )}
       >
         <StatusOrb status={status} size={size} {...props} />
-        <span className="text-xs font-mono text-nothing-gray-600">
+        <span className="text-xs font-body text-nothing-gray-600">
           {displayLabel}
         </span>
       </span>

apps/web/src/components/ui/toast.tsx

@@ -155,7 +155,7 @@ function ToastItem({ toast, onClose }: { toast: ToastItem; onClose: () => void }
           toast.type === 'loading' && 'animate-spin'
         )}
       />
-      <p className={cn('font-mono text-sm', config.text)}>{toast.message}</p>
+      <p className={cn('font-body text-sm', config.text)}>{toast.message}</p>
     </div>
   )
 }