fix: reserve Untitled Project name; rename project will trigger save immidiatly.

src/util/projectNameUtil.ts

@@ -9,6 +9,12 @@ const VALID_PROJECT_NAME_REGEX = /^[a-zA-Z0-9 \-_.()\u00C0-\u024F]+$/;
  */
 const DISALLOWED_CHARS_REGEX = /[^a-zA-Z0-9 \-_.()\u00C0-\u024F]/g;
 
+/**
+ * The reserved project name used for unsaved/new projects.
+ * Users cannot rename a project to this name, and its OPFS folder is wiped on every startup.
+ */
+export const RESERVED_PROJECT_NAME = "Untitled Project";
+
 /**
  * Validate whether a project name contains only allowed characters.
  * Does NOT check for empty string — caller should check that separately.
@@ -19,6 +25,13 @@ export function isValidProjectName(name: string): boolean {
   return VALID_PROJECT_NAME_REGEX.test(name);
 }
 
+/**
+ * Returns true if the given name matches the reserved "Untitled Project" name.
+ */
+export function isReservedProjectName(name: string): boolean {
+  return name.trim() === RESERVED_PROJECT_NAME;
+}
+
 /**
  * Sanitize a project name by replacing disallowed characters with underscores,
  * collapsing consecutive underscores/spaces, and trimming.
@@ -37,7 +50,7 @@ export function sanitizeProjectName(name: string): string {
 
   // If everything was stripped, provide a fallback
   if (sanitized.length === 0) {
-    sanitized = 'Untitled Project';
+    sanitized = RESERVED_PROJECT_NAME;
   }
 
   return sanitized;