feat(config): badges statut + suppression par provider dans Clés API IA

- backend: ajout DELETE /api/config/ai-keys/{provider_env} pour supprimer une clé
- frontend: badge ✓ Configuré / Non configuré sur chaque ligne provider
- frontend: bouton × Supprimer avec confirmation sur les providers configurés
- testAIKeys met à jour les badges selon les résultats du test

backend/main.py

@@ -4022,6 +4022,25 @@ async def api_set_ai_keys(body: dict = Body(...), current_user=Depends(require_a
     logger.info("AI keys updated")
     return {"status": "ok"}
 
+
+@app.delete("/api/config/ai-keys/{provider_env}")
+async def api_delete_ai_key(provider_env: str, current_user=Depends(require_admin)):
+    """Delete a specific AI provider key from storage."""
+    allowed = {"DEEPSEEK_API_KEY", "OPENROUTER_API_KEY", "GEMINI_API_KEY",
+               "NVIDIA_API_KEY", "QWENCLOUD_API_KEY", "XIAOMI_API_KEY", "MISTRAL_API_KEY"}
+    key_name = provider_env.upper()
+    if key_name not in allowed:
+        raise HTTPException(status_code=400, detail=f"Clé inconnue: {provider_env}")
+    keys = _read_ai_keys()
+    if key_name in keys:
+        del keys[key_name]
+        _write_ai_keys(keys)
+    # Also clear from env at runtime so get_ai_key() no longer finds it
+    os.environ.pop(key_name, None)
+    logger.info(f"AI key deleted: {key_name}")
+    return {"status": "deleted", "key": key_name}
+
+
 @app.post("/api/config/ai-keys/test")
 async def api_test_ai_keys(current_user=Depends(require_admin)):
     """Test which AI providers are configured.