fix: FLUX.2-klein prompt keyword arg, image for all verdicts

app.py

@@ -345,18 +345,12 @@ def submit_answer(question, chunk, student_answer, correct, total, language):
         return f"Erreur : {e}", correct, total, _score_label(correct, total)
 
 
-def _is_positive_verdict(feedback: str) -> bool:
-    """True for Correct or Partially Correct verdicts (not Incorrect / errors)."""
-    for line in feedback.splitlines():
-        low = line.lower()
-        if "verdict" in low:
-            return "correct" in low and "incorrect" not in low
-    return False
-
-
 @spaces.GPU(duration=60)
 def generate_image_fn(question, feedback):
-    if not question or not _is_positive_verdict(feedback):
+    if not question or not feedback:
+        return None
+    low = feedback.strip().lower()
+    if low.startswith("erreur") or low.startswith("⚠"):
         return None
     try:
         concept = question.strip().replace("\n", " ")[:200]

core/image_gen.py

@@ -30,10 +30,10 @@ def generate_concept_image(concept: str) -> Image.Image:
         "scientific diagram style"
     )
     result = pipe(
-        prompt,
+        prompt=prompt,
         height=512,
         width=512,
         num_inference_steps=4,
-        guidance_scale=0.0,
+        guidance_scale=1.0,
     )
     return result.images[0]