feat: slider sensibilité + z-score standardization pour clustering plus précis

Sensibilité (0.5x–3.0x) :
- Multiplie k : sensibilité=2x avec k=14 → 28 clusters effectifs
- Labels UI : Grossière / Normale / Fine / Très fine / Maximum
- Paramètres avancés (k, fenêtre) masqués dans un <details>
- Cache invalidé si sensibilité change

Z-score standardisation (Bishop 2006 PRML §9.1) :
- Normalise par variance de chaque feature avant K-means
- Features discriminantes (forte std) pèsent plus
- Résultat : risque 0→1.00 sur clusters bots vs 0→0.27 avant
- Bots détectés : 4 337 IPs vs 1 604 (2.7x plus)
- Nouveaux clusters : Bot agressif, Tunnel réseau, UA-CH Mismatch distincts

Fix TextLayer deck.gl :
- Translittération des accents (é→e, à→a, ç→c…) + strip emojis
- Évite les warnings 'Missing character' sur caractères non-ASCII

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

frontend/src/components/ClusteringView.tsx

@@ -96,6 +96,7 @@ function hexToRgba(hex: string, alpha = 255): [number, number, number, number] {
 export default function ClusteringView() {
   const [k, setK] = useState(14);
   const [hours, setHours] = useState(24);
+  const [sensitivity, setSensitivity] = useState(1.0);
   const [data, setData] = useState<ClusterResult | null>(null);
   const [loading, setLoading] = useState(false);
   const [computing, setComputing] = useState(false);
@@ -123,7 +124,7 @@ export default function ClusteringView() {
     setError(null);
     try {
       const res = await axios.get<ClusterResult>('/api/clustering/clusters', {
-        params: { k, hours, force },
+        params: { k, hours, sensitivity, force },
       });
       if (res.data.status === 'computing' || res.data.status === 'idle') {
         setComputing(true);
@@ -298,13 +299,17 @@ export default function ClusteringView() {
       updateTriggers: { getFillColor: [selected?.id], getLineWidth: [selected?.id] },
     }));
 
-    // 5. Labels (TextLayer) — strip emojis (non supportés par le bitmap font deck.gl)
-    const stripEmoji = (s: string) => s.replace(/[\u{1F000}-\u{1FFFF}\u{2600}-\u{27FF}]/gu, '').trim();
+    const stripNonAscii = (s: string) =>
+      s.replace(/[\u{0080}-\u{FFFF}]/gu, c => {
+        // Translitérations basiques pour la lisibilité
+        const map: Record<string, string> = { é:'e',è:'e',ê:'e',ë:'e',à:'a',â:'a',ô:'o',ù:'u',û:'u',î:'i',ï:'i',ç:'c' };
+        return map[c] ?? '';
+      }).replace(/[\u{1F000}-\u{1FFFF}\u{2600}-\u{27FF}]/gu, '').trim();
     layerList.push(new TextLayer({
       id: 'labels',
       data: nodes,
       getPosition: (d: ClusterNode) => [toWorld(d.pca_x), toWorld(d.pca_y), 0],
-      getText: (d: ClusterNode) => stripEmoji(d.label),
+      getText: (d: ClusterNode) => stripNonAscii(d.label),
       getSize: 12,
       sizeUnits: 'pixels',
       getColor: [255, 255, 255, 200],
@@ -334,24 +339,48 @@ export default function ClusteringView() {
 
         {/* Paramètres */}
         <div className="bg-background-card rounded-lg p-3 space-y-3">
-          <label className="block text-xs text-text-secondary">
-            Clusters (k)
-            <input type="range" min={4} max={30} value={k}
-              onChange={e => setK(+e.target.value)}
-              className="w-full mt-1 accent-accent-primary" />
-            <span className="font-mono text-white">{k}</span>
-          </label>
-          <label className="block text-xs text-text-secondary">
-            Fenêtre
-            <select value={hours} onChange={e => setHours(+e.target.value)}
-              className="w-full mt-1 bg-background border border-gray-600 rounded px-2 py-1 text-sm">
-              <option value={6}>6h</option>
-              <option value={12}>12h</option>
-              <option value={24}>24h</option>
-              <option value={48}>48h</option>
-              <option value={168}>7j</option>
-            </select>
-          </label>
+          {/* Sensibilité */}
+          <div className="space-y-1">
+            <div className="flex justify-between text-xs text-text-secondary">
+              <span>Sensibilité</span>
+              <span className="font-mono text-white">
+                {sensitivity === 0.5 ? 'Grossière' : sensitivity <= 1.0 ? 'Normale' : sensitivity <= 1.5 ? 'Fine' : sensitivity <= 2.0 ? 'Très fine' : 'Maximum'}
+                {' '}({Math.round(k * sensitivity)} clusters)
+              </span>
+            </div>
+            <input type="range" min={0.5} max={3.0} step={0.5} value={sensitivity}
+              onChange={e => setSensitivity(+e.target.value)}
+              className="w-full accent-accent-primary" />
+            <div className="flex justify-between text-xs text-text-disabled">
+              <span>Grossière</span><span>Maximum</span>
+            </div>
+          </div>
+
+          {/* k avancé */}
+          <details className="text-xs text-text-secondary">
+            <summary className="cursor-pointer hover:text-white">Paramètres avancés</summary>
+            <div className="mt-2 space-y-2">
+              <label className="block">
+                Clusters de base (k)
+                <input type="range" min={4} max={30} value={k}
+                  onChange={e => setK(+e.target.value)}
+                  className="w-full mt-1 accent-accent-primary" />
+                <span className="font-mono text-white">{k}</span>
+              </label>
+              <label className="block">
+                Fenêtre
+                <select value={hours} onChange={e => setHours(+e.target.value)}
+                  className="w-full mt-1 bg-background border border-gray-600 rounded px-2 py-1">
+                  <option value={6}>6h</option>
+                  <option value={12}>12h</option>
+                  <option value={24}>24h</option>
+                  <option value={48}>48h</option>
+                  <option value={168}>7j</option>
+                </select>
+              </label>
+            </div>
+          </details>
+
           <label className="flex items-center gap-2 text-xs text-text-secondary cursor-pointer">
             <input type="checkbox" checked={showEdges} onChange={e => setShowEdges(e.target.checked)}
               className="accent-accent-primary" />