fix: PAUSED resume after server restart, diff viewer only shows last tool

apps/tui/src/main/kotlin/com/correx/apps/tui/TuiApp.kt

@@ -163,9 +163,9 @@ private fun renderIdleLayout(frame: Frame, state: TuiState) {
 private fun renderInSessionLayout(frame: Frame, state: TuiState) {
     val area = frame.area()
     val selectedSession = state.sessions.sessions.firstOrNull { it.id == state.sessions.selectedId }
-    val hasDiff = selectedSession?.tools?.any {
-        it.status == ToolDisplayStatus.COMPLETED && it.diff != null
-    } == true
+    val hasDiff = selectedSession?.tools
+        ?.lastOrNull { it.status == ToolDisplayStatus.COMPLETED }
+        ?.diff != null
 
     val constraints = mutableListOf(
         Constraint.length(STATUS_HEIGHT),
@@ -197,12 +197,20 @@ private fun renderInSessionLayout(frame: Frame, state: TuiState) {
 
 private fun renderApprovalLayout(frame: Frame, state: TuiState) {
     val area = frame.area()
+    val selectedSession = state.sessions.sessions.firstOrNull { it.id == state.sessions.selectedId }
+    val hasDiff = selectedSession?.tools
+        ?.lastOrNull { it.status == ToolDisplayStatus.COMPLETED }
+        ?.diff != null
+
     val constraints = mutableListOf(
         Constraint.length(STATUS_HEIGHT),
     )
     if (state.eventStripVisible) {
         constraints.add(Constraint.length(EVENT_STRIP_HEIGHT))
     }
+    if (hasDiff) {
+        constraints.add(Constraint.length(DIFF_HEIGHT))
+    }
     constraints.add(Constraint.fill())
     constraints.add(Constraint.length(INPUT_HEIGHT))
 
@@ -215,6 +223,9 @@ private fun renderApprovalLayout(frame: Frame, state: TuiState) {
     if (state.eventStripVisible) {
         frame.renderWidget(eventHistoryStripWidget(state), vertRects[rectIdx++])
     }
+    if (hasDiff) {
+        frame.renderWidget(diffViewerWidget(state), vertRects[rectIdx++])
+    }
     frame.renderWidget(approvalSurfaceWidget(state), vertRects[rectIdx++])
     frame.renderWidget(inputBarWidget(state, DisplayState.APPROVAL), vertRects[rectIdx])
 }

apps/tui/src/main/kotlin/com/correx/apps/tui/components/DiffViewer.kt

@@ -23,8 +23,11 @@ private val yellowStyle = Style.create().yellow()
 fun diffViewerWidget(state: TuiState): Paragraph {
     val selectedSession = state.sessions.sessions.firstOrNull { it.id == state.sessions.selectedId }
 
+    // Only show the diff for the most recently completed tool. If the last tool has no diff
+    // (e.g. a shell command), the viewer is hidden — stale diffs from earlier tools are noise.
     val toolWithDiff = selectedSession?.tools
-        ?.lastOrNull { it.status == ToolDisplayStatus.COMPLETED && it.diff != null }
+        ?.lastOrNull { it.status == ToolDisplayStatus.COMPLETED }
+        ?.takeIf { it.diff != null }
 
     val diffText = toolWithDiff?.diff ?: return Paragraph.builder().build()