gui: fix tool block rendering — use blockRenderedHtml directly

The Repeater-over-segments approach was failing to display tool output.
When a complete block arrives in one streaming chunk, QML's Repeater
with a var-typed model doesn't reliably re-render delegates on property
changes.

Fix: use a single TextEdit bound to blockRenderedHtml for all non-diagram
blocks. The Repeater path is retained only for blocks containing diagrams
(which need the Loader/component switching). This is simpler, more
reliable, and avoids the Repeater delegate lifecycle issues.

gui/ChatBlockDelegate.qml

@@ -11,6 +11,7 @@ Column {
     required property string blockType
     required property string blockName
     required property var blockSegments
+    required property string blockRenderedHtml
 
     // Reference to parent ListView for scroll control
     property ListView parentListView: null
@@ -119,8 +120,60 @@ Column {
         visible: root.blockExpanded
         spacing: 4
 
+        // Fast path: single TextEdit for the concatenated HTML.
+        // Diagrams are handled separately via the segments list.
+        TextEdit {
+            id: mainTextEdit
+            width: root.width
+            visible: !hasDiagrams()
+            text: root.blockRenderedHtml
+            textFormat: Text.RichText
+            readOnly: true
+            selectByMouse: true
+            persistentSelection: true
+            wrapMode: TextEdit.Wrap
+            font.family: theme.fontFamily || Qt.application.font.family
+            font.pointSize: theme.fontSize > 0 ? theme.fontSize : 12
+            selectionColor: theme.highlightColor
+            selectedTextColor: theme.highlightedTextColor
+
+            onActiveFocusChanged: {
+                if (!activeFocus && root.parentListView)
+                    root.parentListView.interactive = true
+            }
+
+            MouseArea {
+                anchors.fill: parent
+                acceptedButtons: Qt.LeftButton
+                propagateComposedEvents: true
+                cursorShape: Qt.IBeamCursor
+                onPressed: function(mouse) {
+                    if (root.parentListView) root.parentListView.interactive = false
+                    mouse.accepted = false
+                }
+                onReleased: function(mouse) {
+                    if (root.parentListView) root.parentListView.interactive = true
+                    mouse.accepted = false
+                }
+            }
+
+            MouseArea {
+                anchors.fill: parent
+                acceptedButtons: Qt.RightButton
+                cursorShape: Qt.IBeamCursor
+                onClicked: {
+                    if (!mainTextEdit._menu) {
+                        mainTextEdit._menu = contextMenuComponent.createObject(mainTextEdit)
+                    }
+                    mainTextEdit._menu.popup()
+                }
+            }
+            property var _menu: null
+        }
+
+        // Diagram path: use Repeater for blocks that contain diagrams
         Repeater {
-            model: root.blockSegments || []
+            model: hasDiagrams() ? root.blockSegments : []
 
             delegate: Loader {
                 width: root.width
@@ -131,6 +184,15 @@ Column {
         }
     }
 
+    function hasDiagrams() {
+        if (!root.blockSegments) return false
+        for (var i = 0; i < root.blockSegments.length; i++) {
+            if (root.blockSegments[i] && root.blockSegments[i].type === "diagram")
+                return true
+        }
+        return false
+    }
+
     // Text segment component
     Component {
         id: textComponent