style(web): AI 工作台附件卡片样式与交互适配

- personal-workbench-ai-mode.css 新增 workbench-ai-file-card 系列样式，file-strip 改为 flex-wrap 左对齐排布卡片，移除按钮样式随卡片重构
- workbench-ai-mode-switch 测试补充附件卡片相关断言

web/src/assets/styles/components/personal-workbench-ai-mode.css

@@ -214,7 +214,7 @@
 .workbench-ai-icon-btn,
 .workbench-ai-send-btn,
 .workbench-ai-action,
-.workbench-ai-file-strip button {
+.workbench-ai-file-card__remove {
   border: 0;
   cursor: pointer;
   transition:
@@ -294,7 +294,7 @@
 }
 
 .workbench-ai-action:hover,
-.workbench-ai-file-strip button:hover {
+.workbench-ai-file-card__remove:hover {
   transform: translateY(-1px);
   border-color: rgba(47, 124, 255, 0.1);
   box-shadow: 0 8px 24px rgba(0, 0, 0, 0.05);
@@ -456,9 +456,10 @@
 .workbench-ai-file-strip {
   width: min(980px, 100%);
   display: flex;
+  flex-wrap: wrap;
   align-items: center;
-  justify-content: center;
-  gap: 12px;
+  justify-content: flex-start;
+  gap: 10px;
   color: var(--ai-muted);
   font-size: 13px;
   font-weight: 700;
@@ -466,15 +467,100 @@
   animation-delay: 340ms;
 }
 
-.workbench-ai-file-strip button {
-  min-height: 30px;
-  padding: 0 12px;
-  border: 1px solid rgba(47, 124, 255, 0.18);
-  border-radius: 8px;
-  background: rgba(255, 255, 255, 0.82);
-  color: var(--ai-blue);
-  font-size: 13px;
+.workbench-ai-file-card {
+  flex: 0 1 312px;
+  min-width: 238px;
+  min-height: 64px;
+  display: grid;
+  grid-template-columns: 48px minmax(0, 1fr) 30px;
+  align-items: center;
+  gap: 12px;
+  padding: 10px 10px 10px 12px;
+  border: 1px solid rgba(203, 213, 225, 0.76);
+  border-radius: 16px;
+  background:
+    linear-gradient(180deg, rgba(255, 255, 255, 0.96), rgba(248, 250, 252, 0.9));
+  box-shadow:
+    0 10px 28px rgba(15, 23, 42, 0.06),
+    inset 0 1px 0 rgba(255, 255, 255, 0.94);
+}
+
+.workbench-ai-file-card__icon {
+  width: 48px;
+  height: 48px;
+  display: inline-grid;
+  place-items: center;
+  border-radius: 13px;
+  background: #111827;
+  color: #ff6b6b;
+  font-size: 24px;
+  line-height: 1;
+}
+
+.workbench-ai-file-card__icon.type-image {
+  color: #38bdf8;
+}
+
+.workbench-ai-file-card__icon.type-spreadsheet {
+  color: #34d399;
+}
+
+.workbench-ai-file-card__icon.type-document {
+  color: #93c5fd;
+}
+
+.workbench-ai-file-card__icon.type-archive,
+.workbench-ai-file-card__icon.type-file {
+  color: #c4b5fd;
+}
+
+.workbench-ai-file-card__body {
+  min-width: 0;
+  display: grid;
+  gap: 4px;
+}
+
+.workbench-ai-file-card__body strong,
+.workbench-ai-file-card__body small {
+  display: block;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.workbench-ai-file-card__body strong {
+  color: #1e293b;
+  font-size: 15px;
   font-weight: 800;
+  line-height: 1.25;
+}
+
+.workbench-ai-file-card__body small {
+  color: #7b8799;
+  font-size: 13px;
+  font-weight: 760;
+  letter-spacing: 0;
+}
+
+.workbench-ai-file-card__remove {
+  width: 30px;
+  height: 30px;
+  display: inline-grid;
+  place-items: center;
+  align-self: start;
+  border: 1px solid rgba(203, 213, 225, 0.72);
+  border-radius: 999px;
+  background: #ffffff;
+  color: #475569;
+  font-size: 18px;
+  line-height: 1;
+}
+
+.workbench-ai-file-card__remove:disabled {
+  cursor: not-allowed;
+  opacity: 0.48;
+  transform: none;
+  box-shadow: none;
 }
 
 .workbench-ai-quick-start-section {