feat: no default task/version selected on startup, button guides user to pick mode

toothmap_frontend/src/App.jsx

@@ -188,10 +188,10 @@ export default function App() {
   const [file, setFile] = useState(null);
   const [imagePreview, setImagePreview] = useState(null);
   
-  // Tasks: 'diagnostic', 'segmentation', 'charting'
-  const [task, setTask] = useState('charting');
-  // Versions: 'v1' (YOLO), 'v2' (FasterRCNN)
-  const [version, setVersion] = useState('v1');
+  // Tasks: 'diagnostic', 'segmentation', 'charting' — null = nothing selected
+  const [task, setTask] = useState(null);
+  // Versions: 'v1' (YOLO), 'v2' (FasterRCNN) — null = nothing selected
+  const [version, setVersion] = useState(null);
   
   const [pipelineResults, setPipelineResults] = useState(null);
   const [rawBoxes, setRawBoxes] = useState(null);
@@ -201,6 +201,7 @@ export default function App() {
   const canvasRef = useRef(null);
 
   const modeStr = (() => {
+    if (!task || !version) return null;
     if (task === 'diagnostic') return version === 'v1' ? 'yolo' : 'frcnn';
     if (task === 'segmentation') return version === 'v1' ? 'seg_yolo' : 'seg_frcnn';
     if (task === 'charting') return version === 'v1' ? 'pipeline_yolo' : 'pipeline_frcnn';
@@ -217,7 +218,7 @@ export default function App() {
   };
 
   const handleAPI = async () => {
-    if (!file) return;
+    if (!file || !modeStr) return;
     setLoading(true);
     setPipelineResults(null); setRawBoxes(null); setMaskSrc(null);
     const fd = new FormData();
@@ -421,9 +422,9 @@ export default function App() {
           {/* Analyze Button */}
           <button
             onClick={handleAPI}
-            disabled={!file || loading}
+            disabled={!file || !task || !version || loading}
             className={`w-full py-2.5 rounded-xl font-bold text-[13px] flex items-center justify-center gap-2 transition-all duration-200 shadow-md ${
-              !file
+              !file || !task || !version
                 ? 'bg-[#1a1a1f] text-zinc-600 border border-white/5 cursor-not-allowed'
                 : loading
                   ? 'bg-blue-700 text-white cursor-wait'
@@ -431,7 +432,12 @@ export default function App() {
             }`}
           >
             {loading ? <Loader2 size={16} className="animate-spin" /> : <ScanLine size={16} />}
-            {loading ? 'Analyse en cours…' : `Lancer l'analyse IA — ${task === 'diagnostic' ? 'Détection' : task === 'segmentation' ? 'Segmentation' : 'Analyse complète'}`}
+            {loading
+              ? 'Analyse en cours…'
+              : !task || !version
+                ? 'Sélectionnez un mode et une version'
+                : `Lancer l'analyse IA — ${task === 'diagnostic' ? 'Détection' : task === 'segmentation' ? 'Segmentation' : 'Analyse complète'}`
+            }
           </button>
 
           {/* Stats Row */}