fix: 日志区改用 dock 布局自动占满剩余空间

- monitor-area: dock top
- input-area: dock bottom, height 3
- main-area: 自动填充中间所有空白
- 去掉 grid 布局避免高度塌缩

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

services/tui_service.py

@@ -551,30 +551,27 @@ class TUIFramework(App):
     
     
     def _generate_css(self):
-        """动态生成 CSS — 标题 + 状态栏 + 主内容 + 底部输入"""
+        """动态生成 CSS — dock 布局：标题 + 状态栏 + 主内容 + 底部输入"""
         return """
-    Screen {
-        layout: grid;
-        grid-size: 1 4;
-        grid-rows: auto auto 1fr 3;
-    }
-
     #monitor-area {
+        dock: top;
         padding: 1 1 0 1;
         background: $panel;
         color: $text;
+        height: auto;
+    }
+
+    #input-area {
+        dock: bottom;
+        padding: 0 1;
+        height: 3;
+        align: center bottom;
     }
 
     #main-area {
         overflow-y: auto;
         scrollbar-size: 1 1;
         border: solid $primary;
-        min-height: 10;
-    }
-
-    #input-area {
-        padding: 0 1;
-        align: center bottom;
     }
 
     ScrollableContainer {