refactor(editor): remove unused scroll-related code

- Delete unused `scrollToSrcOffset` function in `McpPreviewEditor`
- Remove `VisibleAreaListener` implementation and related imports in `McpFileEditorWithPreview`

Author: phodal

core/src/main/kotlin/cc/unitmesh/devti/mcp/editor/McpFileEditorWithPreview.kt

@@ -2,10 +2,6 @@ package cc.unitmesh.devti.mcp.editor
 
 import com.intellij.icons.AllIcons
 import com.intellij.openapi.actionSystem.*
-import com.intellij.openapi.editor.event.VisibleAreaEvent
-import com.intellij.openapi.editor.event.VisibleAreaListener
-import com.intellij.openapi.editor.ex.util.EditorUtil
-import com.intellij.openapi.editor.impl.EditorImpl
 import com.intellij.openapi.fileEditor.TextEditor
 import com.intellij.openapi.fileEditor.TextEditorWithPreview
 import com.intellij.openapi.fileEditor.impl.text.TextEditorProvider
@@ -22,29 +18,12 @@ class McpFileEditorWithPreview(
 
     init {
         preview.setMainEditor(ourEditor.editor)
-        ourEditor.editor.scrollingModel.addVisibleAreaListener(MyVisibleAreaListener(), this)
     }
 
     override fun dispose() {
         TextEditorProvider.getInstance().disposeEditor(ourEditor)
     }
 
-    inner class MyVisibleAreaListener : VisibleAreaListener {
-        private var previousLine = 0
-
-        override fun visibleAreaChanged(event: VisibleAreaEvent) {
-            val editor = event.editor
-            val y = editor.scrollingModel.verticalScrollOffset
-            val currentLine = if (editor is EditorImpl) editor.yToVisualLine(y) else y / editor.lineHeight
-            if (currentLine == previousLine) {
-                return
-            }
-
-            previousLine = currentLine
-            preview.scrollToSrcOffset(EditorUtil.getVisualLineEndOffset(editor, currentLine))
-        }
-    }
-
     override fun createToolbar(): ActionToolbar {
         return ActionManager.getInstance()
             .createActionToolbar(ActionPlaces.EDITOR_TOOLBAR, createActionGroup(project), true)

core/src/main/kotlin/cc/unitmesh/devti/mcp/editor/McpPreviewEditor.kt

@@ -289,10 +289,6 @@ open class McpPreviewEditor(
         mainEditor.value = editor
     }
 
-    fun scrollToSrcOffset(offset: Int) {
-        // Implementation here
-    }
-
     override fun getComponent(): JComponent = mainPanel
     override fun getName(): String = "MCP Preview"
     override fun setState(state: FileEditorState) {}