feat: 优化文件管理器的加载体验，异步加载新鲜度数据并添加加载状态指示

ccw/src/templates/dashboard-css/24-prompt-history.css

@@ -90,7 +90,9 @@
   display: grid;
   grid-template-columns: 1fr 400px;
   gap: 1.5rem;
-  align-items: start;
+  align-items: stretch;
+  flex: 1;
+  min-height: 0;
 }
 
 @media (max-width: 1200px) {

ccw/src/templates/dashboard-css/26-claude-manager.css

@@ -94,6 +94,8 @@
 .claude-manager-column.center {
   overflow: hidden;
   height: 100%;
+  display: flex;
+  flex-direction: column;
 }
 
 .claude-manager-column.right {
@@ -286,11 +288,15 @@
   flex: 1;
   overflow-y: auto;
   padding: 1rem;
+  min-height: 0;
+  background: hsl(var(--muted) / 0.3);
+  border-radius: 0 0 0.5rem 0.5rem;
 }
 
 .markdown-content {
   line-height: 1.6;
   color: hsl(var(--foreground));
+  min-height: 100%;
 }
 
 .markdown-content h1 {
@@ -507,10 +513,14 @@
   flex-direction: column;
   align-items: center;
   justify-content: center;
-  height: 100%;
+  flex: 1;
+  min-height: 200px;
   color: hsl(var(--muted-foreground));
   text-align: center;
   padding: 2rem;
+  background: hsl(var(--muted) / 0.3);
+  border-radius: 0.5rem;
+  margin: 0.5rem;
 }
 
 .empty-state i {
@@ -763,6 +773,18 @@
   color: hsl(0, 72%, 51%);
 }
 
+.freshness-badge.loading {
+  background: hsl(var(--muted));
+  color: hsl(var(--muted-foreground));
+  min-width: 28px;
+  animation: pulse 1.5s ease-in-out infinite;
+}
+
+@keyframes pulse {
+  0%, 100% { opacity: 0.5; }
+  50% { opacity: 1; }
+}
+
 /* File tree item freshness states */
 .file-tree-item.freshness-stale {
   border-left: 2px solid hsl(0, 72%, 51%);
@@ -846,6 +868,21 @@
   color: hsl(38, 92%, 50%);
 }
 
+/* Freshness loading state */
+.freshness-loading {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 0.5rem;
+  padding: 1.5rem;
+  color: hsl(var(--muted-foreground));
+  font-size: 0.875rem;
+}
+
+.freshness-loading i {
+  animation: spin 1s linear infinite;
+}
+
 /* ========================================
  * Responsive Design
  * ======================================== */