fix bugs

Signed-off-by: rgrgogu <obsequio.rus@gmail.com>

src/modules/client/pages/CourseCheckout.jsx

@@ -50,7 +50,14 @@ export default function CourseCheckout() {
 
   // Handle PayPal return — capture
   useEffect(() => {
-    if (!returnToken || capturingRef.current) return;
+    // A real PayPal cancel redirect carries BOTH `cancelled=true` (our own
+    // cancelUrl) and `token=<order_id>` (PayPal always appends its own token
+    // to whatever return/cancel URL it's given) — without this guard, both
+    // this effect and the cancellation effect below fired on the same load,
+    // racing a capture call against the cancel and surfacing a confusing
+    // "Pending purchase not found" error toast instead of a clean
+    // cancellation message.
+    if (!returnToken || wasCancelled || capturingRef.current) return;
     capturingRef.current = true;
     setCapturing(true);
     captureCourseOrder(returnToken).then((result) => {

src/modules/client/pages/UnitReader.jsx

@@ -175,8 +175,14 @@ const UnitReader = () => {
         const stub = lessons.find((l) => l.lesson_id === selectedLessonId);
         if (stub?.status === 'completed') return;
         completedSessionRef.current.add(selectedLessonId);
+        // Trust the server's evaluated unit status, not a local "all fetched
+        // lessons read" re-derivation — that drifted from the real completion
+        // requirement (e.g. a unit needing its quiz passed too) and fired a
+        // premature "Unit complete!" toast. Same fix already applied to
+        // upsertLessonProgress's own unitDetail update; UnitList.jsx's
+        // handleMarkComplete already uses this authoritative pattern.
         upsertLessonProgress(lesson.uuid, 'completed', uuid).then((result) => {
-            if (result?.unit && unitDetail && lessons.every((l) => l.lesson_id === selectedLessonId || l.status === 'completed')) {
+            if (result?.unit?.status === 'completed') {
                 toast.success('Unit complete!', { duration: 4000 });
             }
         });