fix(editor): preserve consecutive whitespace in comments in TipTap (#1893)

* fix(editor): preserve consecutive whitespace in comments in TipTap

Ensure multiple spaces in comment content are no longer collapsed when editing/saving by:
- Adding SetContentOptions with parseOptions.preserveWhitespace = 'full'
- Applying those options to all setContent calls (initial load, exit edit mode, post-upload cleanup)
- Enabling preserveWhitespace in editor parseOptions

Previously, repeated spaces were normalized away after setContent(false), causing comments with deliberate spacing to be altered unexpectedly.

No behavioral changes beyond whitespace retention; renders identical except space fidelity.

* fix(editor): use preserveWhitespace true instead of full to avoid duplicate checklist items

The 'full' mode preserves all whitespace including between block elements,
which caused the HTML parser to create extra empty list items from newlines
between <li> tags. Using 'true' preserves whitespace in inline content only,
which still achieves the goal of preserving consecutive spaces in text while
not creating spurious nodes from formatting whitespace.

---------

Co-authored-by: maggch <maggch@outlook.com>

frontend/src/components/input/editor/TipTap.vue

@@ -145,7 +145,7 @@ import {eventToHotkeyString} from '@github/hotkey'
 import EditorToolbar from './EditorToolbar.vue'
 
 import StarterKit from '@tiptap/starter-kit'
-import {Extension, mergeAttributes} from '@tiptap/core'
+import {Extension, mergeAttributes, type SetContentOptions} from '@tiptap/core'
 import {EditorContent, type Extensions, useEditor, VueNodeViewRenderer} from '@tiptap/vue-3'
 import {Plugin, PluginKey} from '@tiptap/pm/state'
 import {marked} from 'marked'
@@ -216,6 +216,12 @@ const tiptapInstanceRef = ref<HTMLInputElement | null>(null)
 
 const {t} = useI18n()
 
+const defaultSetContentOptions: SetContentOptions = {
+	parseOptions: {
+		preserveWhitespace: true,
+	},
+}
+
 const CustomTableCell = TableCell.extend({
 	addAttributes() {
 		return {
@@ -549,6 +555,9 @@ const editor = useEditor({
 	onUpdate: () => {
 		bubbleNow()
 	},
+	parseOptions: {
+		preserveWhitespace: true,
+	},
 })
 
 watch(
@@ -606,7 +615,10 @@ function bubbleSave() {
 }
 
 function exitEditMode() {
-	editor.value?.commands.setContent(lastSavedState, {emitUpdate: false})
+	editor.value?.commands.setContent(lastSavedState, {
+		...defaultSetContentOptions,
+		emitUpdate: false,
+	})
 
 	// Clear draft from localStorage when discarding changes
 	if (props.storageKey) {
@@ -659,7 +671,10 @@ function uploadAndInsertFiles(files: File[] | FileList) {
 		
 		const html = editor.value?.getHTML().replace(UPLOAD_PLACEHOLDER_ELEMENT, '') ?? ''
 
-		editor.value?.commands.setContent(html, {emitUpdate: false})
+		editor.value?.commands.setContent(html, {
+			...defaultSetContentOptions,
+			emitUpdate: false,
+		})
 
 		bubbleNow()
 	})
@@ -733,7 +748,10 @@ onBeforeUnmount(() => {
 
 function setModeAndValue(value: string) {
 	internalMode.value = isEditorContentEmpty(value) ? 'edit' : 'preview'
-	editor.value?.commands.setContent(value, {emitUpdate: false})
+	editor.value?.commands.setContent(value, {
+		...defaultSetContentOptions,
+		emitUpdate: false,
+	})
 }