refactor(devti): improve UI details and error handling

- Add border to CodeHighlightSketch based on language mode- Adjust layout and borders in SingleFileDiffSketch
- Update PlanLangSketch border to match tool window style
- Remove background color setting in PlanToolbarFactory
- Add error handling for change creation in AgentStateService

Author: phodal

core/src/main/kotlin/cc/unitmesh/devti/observer/agent/AgentStateService.kt

@@ -59,12 +59,16 @@ class AgentStateService(val project: Project) {
             }
         }
 
-        val change = createChange(patch)
-        state.changes.add(change)
+        try {
+            val change = createChange(patch)
+            state.changes.add(change)
 
-        ApplicationManager.getApplication().messageBus
-            .syncPublisher(PlanUpdateListener.TOPIC)
-            .onUpdateChange(state.changes)
+            ApplicationManager.getApplication().messageBus
+                .syncPublisher(PlanUpdateListener.TOPIC)
+                .onUpdateChange(state.changes)
+        } catch (e: IOException) {
+            logger<AgentStateService>().info(e)
+        }
     }
 
     private fun createChange(patch: TextFilePatch): Change {

core/src/main/kotlin/cc/unitmesh/devti/sketch/ui/code/CodeHighlightSketch.kt

@@ -100,7 +100,11 @@ open class CodeHighlightSketch(
             editorFragment?.editor?.backgroundColor = JBColor.PanelBackground
         }
 
-        editorFragment?.editor?.setBorder(JBEmptyBorder(1, 0, 0, 0))
+        if (lowercase == "devin") {
+            editorFragment?.editor?.setBorder(JBEmptyBorder(1, 1, 0, 1))
+        } else if(lowercase != "markdown") {
+            editorFragment?.editor?.setBorder(JBEmptyBorder(1, 0, 0, 0))
+        }
     }
 
     override fun getViewText(): String {

core/src/main/kotlin/cc/unitmesh/devti/sketch/ui/patch/SingleFileDiffSketch.kt

@@ -58,7 +58,7 @@ class SingleFileDiffSketch(
     var patch: TextFilePatch,
     val viewDiffAction: () -> Unit
 ) : LangSketch {
-    private val mainPanel: JPanel = JPanel(VerticalLayout(5))
+    private val mainPanel: JPanel = JPanel(VerticalLayout(0))
     private val myHeaderPanel: JPanel = JPanel(BorderLayout())
     private var patchActionPanel: JPanel? = null
     private val oldCode = if (currentFile.isFile && currentFile.exists()) {
@@ -163,10 +163,10 @@ class SingleFileDiffSketch(
         patchActionPanel = JPanel(BorderLayout()).apply {
             add(filePanel, BorderLayout.WEST)
             add(actionPanel, BorderLayout.EAST)
-            border = BorderFactory.createEmptyBorder(4, 4, 4, 4)
+            border = BorderFactory.createEmptyBorder(0, 4, 0, 4)
         }
 
-        val fileContainer = JPanel(BorderLayout(10, 10)).also {
+        val fileContainer = JPanel(BorderLayout(8, 8)).also {
             it.add(patchActionPanel)
         }
         contentPanel.add(fileContainer, BorderLayout.CENTER)

core/src/main/kotlin/cc/unitmesh/devti/sketch/ui/plan/PlanLangSketch.kt

@@ -30,7 +30,10 @@ class PlanLangSketch(
     init {
         if (!isInToolwindow) {
             add(toolbarFactory.createToolbar(this), BorderLayout.NORTH)
-            border = JBUI.Borders.empty(4)
+            border = JBUI.Borders.compound(
+                JBUI.Borders.empty(0, 4),
+                JBUI.Borders.customLine(JBUI.CurrentTheme.ToolWindow.borderColor(), 1)
+            )
         }
 
         renderPlan()

core/src/main/kotlin/cc/unitmesh/devti/sketch/ui/plan/PlanToolbarFactory.kt

@@ -30,18 +30,13 @@ class PlanToolbarFactory(private val project: Project) {
                 this.targetComponent = component
             }
 
-        val bg = JBUI.CurrentTheme.ToolWindow.background()
-        toolbar.component.setBackground(bg)
-
         val titleLabel = JLabel("Plan").apply {
             border = JBUI.Borders.empty(0, 10)
         }
 
         val toolbarPanel = JPanel(BorderLayout()).apply {
             add(titleLabel, BorderLayout.WEST)
             add(toolbar.component, BorderLayout.EAST)
-        }.also {
-            it.background = bg
         }
 
         val toolbarWrapper = Wrapper(JBUI.Panels.simplePanel(toolbarPanel)).also {