fix: only parse complete hashtags (followed by word boundary)

Prevents incomplete hashtags from being saved during typing when
auto-save fires mid-word.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/lib/utils/parseHashtags.ts

@@ -1,9 +1,11 @@
 /**
  * Extract hashtags from text content
- * Matches #word patterns, supporting alphanumeric and underscores
+ * Matches #word patterns followed by word boundary (space, punctuation, or end of text)
+ * This prevents capturing incomplete hashtags during typing
  */
 export function parseHashtags(text: string): string[] {
-	const hashtagRegex = /#([a-zA-Z][a-zA-Z0-9_]*)/g;
+	// Match hashtags followed by word boundary, whitespace, punctuation, or end of string
+	const hashtagRegex = /#([a-zA-Z][a-zA-Z0-9_]*)(?=[\s\p{P}]|$)/gu;
 	const matches = text.matchAll(hashtagRegex);
 	const tags = new Set<string>();
 
@@ -17,6 +19,7 @@ export function parseHashtags(text: string): string[] {
 /**
  * Highlight hashtags in text for display
  * Returns HTML with hashtags wrapped in styled spans
+ * Only highlights complete hashtags (followed by space, punctuation, or end)
  */
 export function highlightHashtags(text: string): string {
 	const escaped = text
@@ -25,7 +28,7 @@ export function highlightHashtags(text: string): string {
 		.replace(/>/g, '&gt;');
 
 	return escaped.replace(
-		/#([a-zA-Z][a-zA-Z0-9_]*)/g,
+		/#([a-zA-Z][a-zA-Z0-9_]*)(?=[\s\p{P}]|$)/gu,
 		'<span class="text-blue-600 font-medium">#$1</span>'
 	);
 }