ENG-1693 Add insert backlink checkbox to ModifyNodeModal with smart defaults

- Add "Insert backlink" checkbox to ModifyNodeModal (create mode only)
- Default true when pre-filled text exists (user had text selected) or existing node is chosen; false otherwise
- Gate backlink insertion in canvas flow and editor command flow on checkbox value

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: trangdoan982

apps/obsidian/src/components/ModifyNodeModal.tsx

@@ -49,6 +49,7 @@ type ModifyNodeFormProps = {
     /** DiscourseRelation.id; when set, relation is created with currentFile as the other end. */
     relationshipId?: string;
     relationshipTargetFile?: TFile;
+    insertBacklink: boolean;
   }) => Promise<void>;
   onCancel: () => void;
   initialTitle?: string;
@@ -83,6 +84,7 @@ export const ModifyNodeForm = ({
   const [selectedRelationshipKey, setSelectedRelationshipKey] = useState<
     string | undefined
   >(undefined);
+  const [insertBacklink, setInsertBacklink] = useState(!!initialTitle);
   const queryEngine = useRef(new QueryEngine(plugin.app));
   const titleInputRef = useRef<HTMLTextAreaElement>(null);
   const popoverRef = useRef<HTMLDivElement>(null);
@@ -278,6 +280,7 @@ export const ModifyNodeForm = ({
       setSelectedExistingNode(file);
       setQuery(file.basename);
       setTitle(file.basename);
+      setInsertBacklink(true);
       // Auto-detect node type from the selected file's frontmatter
       const nodeTypeId = await getNodeTypeIdForFile(plugin, file);
       if (nodeTypeId && selectedFileRef.current === file) {
@@ -291,12 +294,13 @@ export const ModifyNodeForm = ({
   const handleClearSelection = useCallback(() => {
     selectedFileRef.current = null;
     setSelectedExistingNode(null);
+    setInsertBacklink(!!initialTitle);
     setQuery("");
     setTitle("");
     setTimeout(() => {
       titleInputRef.current?.focus();
     }, 50);
-  }, []);
+  }, [initialTitle]);
 
   const handleKeyDown = (e: React.KeyboardEvent<HTMLTextAreaElement>) => {
     if (selectedExistingNode) {
@@ -391,6 +395,7 @@ export const ModifyNodeForm = ({
         selectedExistingNode: selectedExistingNode || undefined,
         relationshipId: selectedRel?.uniqueKey || undefined,
         relationshipTargetFile: currentFile || undefined,
+        insertBacklink,
       });
       onCancel();
     } catch (error) {
@@ -418,6 +423,7 @@ export const ModifyNodeForm = ({
     selectedRelationshipKey,
     currentFile,
     availableRelationships,
+    insertBacklink,
   ]);
 
   return (
@@ -568,6 +574,20 @@ export const ModifyNodeForm = ({
         </div>
       )}
 
+      {!isEditMode && (
+        <div className="setting-item">
+          <div className="setting-item-name">Insert backlink</div>
+          <div className="setting-item-control">
+            <input
+              type="checkbox"
+              checked={insertBacklink}
+              onChange={(e) => setInsertBacklink(e.target.checked)}
+              disabled={isSubmitting}
+            />
+          </div>
+        </div>
+      )}
+
       <div className="modal-button-container mt-5 flex justify-end gap-2">
         <button
           type="button"
@@ -606,6 +626,7 @@ type ModifyNodeModalProps = {
     selectedExistingNode?: TFile;
     relationshipId?: string;
     relationshipTargetFile?: TFile;
+    insertBacklink: boolean;
   }) => Promise<void>;
   initialTitle?: string;
   initialNodeType?: DiscourseNode;
@@ -622,6 +643,7 @@ class ModifyNodeModal extends Modal {
     selectedExistingNode?: TFile;
     relationshipId?: string;
     relationshipTargetFile?: TFile;
+    insertBacklink: boolean;
   }) => Promise<void>;
   private root: Root | null = null;
   private initialTitle?: string;

apps/obsidian/src/components/canvas/utils/nodeCreationFlow.ts

@@ -32,6 +32,7 @@ export const openCreateDiscourseNodeAt = (args: CreateNodeAtArgs): void => {
       selectedExistingNode,
       relationshipId,
       relationshipTargetFile,
+      insertBacklink,
     }) => {
       try {
         // If user selected an existing node, use it instead of creating a new one
@@ -54,11 +55,13 @@ export const openCreateDiscourseNodeAt = (args: CreateNodeAtArgs): void => {
           });
         }
 
-        const src = await addWikilinkBlockrefForFile({
-          app: plugin.app,
-          canvasFile,
-          linkedFile: fileToUse,
-        });
+        const src = insertBacklink
+          ? await addWikilinkBlockrefForFile({
+              app: plugin.app,
+              canvasFile,
+              linkedFile: fileToUse,
+            })
+          : undefined;
 
         let preloadedImageSrc: string | undefined = undefined;
         if (selectedNodeType.keyImage) {

apps/obsidian/src/utils/registerCommands.ts

@@ -22,6 +22,7 @@ type ModifyNodeSubmitParams = {
   selectedExistingNode?: TFile;
   relationshipId?: string;
   relationshipTargetFile?: TFile;
+  insertBacklink: boolean;
 };
 
 export const createModifyNodeModalSubmitHandler = (
@@ -34,9 +35,10 @@ export const createModifyNodeModalSubmitHandler = (
     selectedExistingNode,
     relationshipId,
     relationshipTargetFile,
+    insertBacklink,
   }: ModifyNodeSubmitParams) => {
     if (selectedExistingNode) {
-      if (editor && editor.somethingSelected()) {
+      if (insertBacklink && editor && editor.somethingSelected()) {
         editor?.replaceSelection(`[[${selectedExistingNode.basename}]]`);
       }
       await addRelationIfRequested(plugin, selectedExistingNode, {
@@ -48,7 +50,7 @@ export const createModifyNodeModalSubmitHandler = (
         plugin,
         nodeType,
         text: title,
-        editor,
+        editor: insertBacklink ? editor : undefined,
       });
       if (newFile) {
         await addRelationIfRequested(plugin, newFile, {