feat: add DeepSeek and Minimax (m2.7) translation providers

New providers:
- DeepSeek: direct API with deepseek-chat model, very cost-effective
- Minimax: MiniMax-M1 model via OpenAI-compatible API, supports m2.7

Changes:
- Full provider implementations with retry, health check, batch support
- Provider config with env vars (DEEPSEEK_*, MINIMAX_*)
- Auto-registration in provider registry
- Updated fallback chain to include new providers
- Updated setup-env.sh wizard with options 6 (deepseek) and 7 (minimax)
- Updated manage-keys.sh with new menu entries and provider switching
- Updated docker-compose.yml with new env vars

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/manage-keys.sh

@@ -101,6 +101,8 @@ while true; do
     show_key_status "OpenAI"        "OPENAI_API_KEY"
     show_key_status "DeepL"         "DEEPL_API_KEY"
     show_key_status "OpenRouter"    "OPENROUTER_API_KEY"
+    show_key_status "DeepSeek"      "DEEPSEEK_API_KEY"
+    show_key_status "Minimax"       "MINIMAX_API_KEY"
     show_key_status "Google"        "GOOGLE_API_KEY"
     echo ""
 
@@ -121,7 +123,9 @@ while true; do
     echo "  4) Configurer Stripe (toutes les cles)"
     echo "  5) Changer le mot de passe admin"
     echo "  6) Changer le service de traduction"
-    echo "  7) Tout afficher (attention: secrets visibles)"
+    echo "  7) Configurer DeepSeek"
+    echo "  8) Configurer Minimax (m2.7)"
+    echo "  9) Tout afficher (attention: secrets visibles)"
     echo "  0) Quitter"
     echo ""
     echo -ne "${YELLOW}Choix:${NC} "
@@ -192,10 +196,12 @@ while true; do
         6)
             echo -e "\n${BOLD}--- Service de traduction ---${NC}"
             echo "  Actuel: $(get_env TRANSLATION_SERVICE)"
-            echo "  1) ollama   (local, gratuit)"
-            echo "  2) deepl    (haute qualite)"
-            echo "  3) openai   (GPT)"
+            echo "  1) ollama     (local, gratuit)"
+            echo "  2) deepl      (haute qualite)"
+            echo "  3) openai     (GPT)"
             echo "  4) openrouter (multi-modeles)"
+            echo "  5) deepseek   (bon rapport qualite/prix)"
+            echo "  6) minimax    (MiniMax-M1 / m2.7)"
             echo ""
             echo -ne "  Choix: "
             read -r svc
@@ -204,12 +210,34 @@ while true; do
                 2) set_env "TRANSLATION_SERVICE" "deepl" ;;
                 3) set_env "TRANSLATION_SERVICE" "openai" ;;
                 4) set_env "TRANSLATION_SERVICE" "openrouter" ;;
+                5) set_env "TRANSLATION_SERVICE" "deepseek" ;;
+                6) set_env "TRANSLATION_SERVICE" "minimax" ;;
                 *) echo -e "  ${RED}Choix invalide${NC}" ;;
             esac
             echo -e "  ${GREEN}Service mis a jour${NC}"
             echo -e "  ${YELLOW}Redemarre: docker compose restart backend${NC}"
             ;;
         7)
+            echo -e "\n${BOLD}--- DeepSeek ---${NC}"
+            echo "  Ou: https://platform.deepseek.com/api_keys"
+            echo "  Modele par defaut: deepseek-chat"
+            ask_key "DeepSeek" "DEEPSEEK_API_KEY"
+            if [ -n "$(get_env DEEPSEEK_API_KEY)" ]; then
+                set_env "DEEPSEEK_ENABLED" "true"
+                echo -e "  ${GREEN}Provider DeepSeek active${NC}"
+            fi
+            ;;
+        8)
+            echo -e "\n${BOLD}--- Minimax (m2.7 / MiniMax-M1) ---${NC}"
+            echo "  Ou: https://platform.minimaxi.com/"
+            echo "  Modele par defaut: MiniMax-M1"
+            ask_key "Minimax" "MINIMAX_API_KEY"
+            if [ -n "$(get_env MINIMAX_API_KEY)" ]; then
+                set_env "MINIMAX_ENABLED" "true"
+                echo -e "  ${GREEN}Provider Minimax active${NC}"
+            fi
+            ;;
+        9)
             echo ""
             echo -e "${RED}${BOLD}ATTENTION: Secrets visibles!${NC}"
             echo -ne "${YELLOW}Taper 'oui' pour continuer:${NC} "