feat: 完善 Knowledge 前端页面

- 增强知识库列表和详情展示
- 添加文档上传和管理功能
- 优化创建和编辑流程

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/views/knowledge/knowledge.css

@@ -95,6 +95,27 @@
   border: 1px solid #374151;
 }
 
+/* 文件上传弹窗特殊样式 - 覆盖 kb-dialog */
+.file-upload-dialog.kb-dialog :deep(.el-dialog) {
+  background-color: #1f2937;
+  border-radius: 12px;
+  border: 1px solid #374151;
+}
+
+.file-upload-dialog.kb-dialog :deep(.el-dialog__header) {
+  padding: 16px 24px;
+  border-bottom: 1px solid #374151;
+}
+
+.file-upload-dialog.kb-dialog :deep(.el-dialog__title) {
+  display: none;
+}
+
+.file-upload-dialog.kb-dialog :deep(.el-dialog__body) {
+  padding: 0;
+  background-color: #0f1419;
+}
+
 .kb-dialog :deep(.el-dialog__header) {
   padding: 20px 24px;
   border-bottom: 1px solid #374151;
@@ -575,23 +596,27 @@
 
 /* 文件上传弹窗布局 */
 .file-upload-dialog .el-dialog {
-  position: absolute !important;
-  top: 8px !important;
-  left: 50% !important;
-  transform: translateX(-50%) !important;
-  margin-bottom: 8px !important;
-  max-height: calc(100vh - 16px);
+  margin: auto !important;
+  top: 20px !important;
+  bottom: 20px !important;
+  height: auto !important;
+  max-height: calc(100vh - 40px);
+  overflow: hidden;
 }
 
 .file-upload-dialog .el-dialog__body {
   padding: 0;
+  height: calc(100vh - 80px);
+  max-height: calc(100vh - 80px);
+  overflow: hidden;
 }
 
 .file-upload-layout {
   display: flex;
   flex-direction: column;
-  height: 85vh;
+  height: 100%;
   background-color: #0f1419;
+  overflow: hidden;
 }
 
 /* 顶部导航 */
@@ -669,6 +694,26 @@
   padding: 12px;
 }
 
+.loading-state,
+.empty-state {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  padding: 40px 20px;
+  color: #6b7280;
+  gap: 12px;
+}
+
+.loading-state i,
+.empty-state i {
+  font-size: 32px;
+}
+
+.empty-state i {
+  color: #4b5563;
+}
+
 .file-item {
   display: flex;
   align-items: center;
@@ -744,10 +789,41 @@
   color: #ef4444;
 }
 
+.file-item-status .status-text {
+  font-size: 12px;
+  color: #ef4444;
+}
+
 .file-item-status.parsing i {
   color: #f59e0b;
 }
 
+.file-item-delete {
+  flex-shrink: 0;
+  width: 24px;
+  height: 24px;
+  border-radius: 4px;
+  border: none;
+  background: transparent;
+  color: #6b7280;
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  opacity: 0;
+  transition: all 0.2s;
+  margin-left: 4px;
+}
+
+.file-item:hover .file-item-delete {
+  opacity: 1;
+}
+
+.file-item-delete:hover {
+  background-color: rgba(239, 68, 68, 0.15);
+  color: #ef4444;
+}
+
 /* 右侧预览面板 */
 .file-preview {
   flex: 1;
@@ -756,6 +832,47 @@
   background-color: #121218;
 }
 
+.preview-empty {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  color: #6b7280;
+  gap: 12px;
+}
+
+.preview-empty i {
+  font-size: 48px;
+  color: #4b5563;
+}
+
+.preview-empty span {
+  font-size: 14px;
+}
+
+.preview-loading,
+.preview-no-file {
+  flex: 1;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  justify-content: center;
+  color: #6b7280;
+  gap: 12px;
+}
+
+.preview-loading i,
+.preview-no-file i {
+  font-size: 48px;
+  color: #4b5563;
+}
+
+.preview-loading span,
+.preview-no-file span {
+  font-size: 14px;
+}
+
 .preview-header {
   display: flex;
   align-items: center;
@@ -817,7 +934,8 @@
   background-color: #1a1a1a;
 }
 
-.pdf-iframe {
+.pdf-iframe,
+.pdf-embed {
   width: 100%;
   height: 100%;
   border: none;