fix(find-replace): 修正面板定位及拖拽边界限制

- 将查找替换面板定位由绝对定位改为固定定位，提升稳定性
- 拖拽过程中避免重复查询面板元素，优化性能
- 增加拖拽边界限制，保证面板至少保留一定可视区域
- 通过计算移动增量并限制偏移，防止面板超出浏览器视口
- 保持面板在窗口内可见性，提升用户体验

src/views/editor/components/EditorPanel/components/FindReplacePanel/functionals/index.ts

@@ -247,11 +247,31 @@ export function useDraggable(visible: Ref<boolean>) {
         const initialX = dragOffset.value.x
         const initialY = dragOffset.value.y
 
+        // 在拖拽开始时记录面板元素，避免 mousemove 中反复 querySelector
+        const panelEl = (e.currentTarget as HTMLElement)?.closest('.find-replace-panel') as HTMLElement | null
+
         const onMouseMove = (moveEvt: MouseEvent) => {
             if (!dragging.value) return
-            dragOffset.value = {
-                x: initialX + moveEvt.clientX - startX,
-                y: initialY + moveEvt.clientY - startY
+            const rawX = initialX + moveEvt.clientX - startX
+            const rawY = initialY + moveEvt.clientY - startY
+
+            if (panelEl) {
+                // 以当前 rect 为基准，计算本次移动的 delta 并 clamp
+                // 保证面板至少有 keepVisible px 留在视口内
+                const rect = panelEl.getBoundingClientRect()
+                const vw = window.innerWidth
+                const vh = window.innerHeight
+                const keepVisible = 80
+                const deltaX = rawX - dragOffset.value.x
+                const deltaY = rawY - dragOffset.value.y
+                const clampedDeltaX = Math.min(vw - keepVisible - rect.left, Math.max(keepVisible - rect.right, deltaX))
+                const clampedDeltaY = Math.min(vh - keepVisible - rect.top, Math.max(keepVisible - rect.bottom, deltaY))
+                dragOffset.value = {
+                    x: dragOffset.value.x + clampedDeltaX,
+                    y: dragOffset.value.y + clampedDeltaY
+                }
+            } else {
+                dragOffset.value = { x: rawX, y: rawY }
             }
         }
 

src/views/editor/components/EditorPanel/components/FindReplacePanel/index.vue

@@ -3,7 +3,7 @@
         <transition name="slide-fade">
             <div
                 v-if="visible"
-                class="find-replace-panel absolute top-20 right-4 z-[999] bg-card/90 backdrop-blur-md border border-divider shadow-2xl rounded-xl p-4 flex flex-col space-y-3 select-none"
+                class="find-replace-panel fixed top-20 right-4 z-[999] bg-card/90 backdrop-blur-md border border-divider shadow-2xl rounded-xl p-4 flex flex-col space-y-3 select-none"
                 :style="{
                     width: computedWidth,
                     height: computedHeight,