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>

services/providers/config.py

@@ -96,12 +96,31 @@ class ProvidersConfig:
     OPENROUTER_API_KEY: str = os.getenv("OPENROUTER_API_KEY", "")
     OPENROUTER_MODEL: str = os.getenv("OPENROUTER_MODEL", "deepseek/deepseek-chat")
 
+    # DeepSeek (direct API)
+    DEEPSEEK_ENABLED: bool = os.getenv("DEEPSEEK_ENABLED", "false").lower() == "true"
+    DEEPSEEK_API_KEY: str = os.getenv("DEEPSEEK_API_KEY", "")
+    DEEPSEEK_MODEL: str = os.getenv("DEEPSEEK_MODEL", "deepseek-chat")
+    DEEPSEEK_BASE_URL: str = os.getenv("DEEPSEEK_BASE_URL", "https://api.deepseek.com/v1")
+    DEEPSEEK_TIMEOUT: int = int(os.getenv("DEEPSEEK_TIMEOUT", "60"))
+    DEEPSEEK_MAX_RETRIES: int = int(os.getenv("DEEPSEEK_MAX_RETRIES", "3"))
+    DEEPSEEK_RETRY_DELAY: float = float(os.getenv("DEEPSEEK_RETRY_DELAY", "1.0"))
+
+    # Minimax (direct API - m2.7, MiniMax-M1)
+    MINIMAX_ENABLED: bool = os.getenv("MINIMAX_ENABLED", "false").lower() == "true"
+    MINIMAX_API_KEY: str = os.getenv("MINIMAX_API_KEY", "")
+    MINIMAX_MODEL: str = os.getenv("MINIMAX_MODEL", "MiniMax-M1")
+    MINIMAX_BASE_URL: str = os.getenv("MINIMAX_BASE_URL", "https://api.minimax.chat/v1")
+    MINIMAX_GROUP_ID: str = os.getenv("MINIMAX_GROUP_ID", "")
+    MINIMAX_TIMEOUT: int = int(os.getenv("MINIMAX_TIMEOUT", "60"))
+    MINIMAX_MAX_RETRIES: int = int(os.getenv("MINIMAX_MAX_RETRIES", "3"))
+    MINIMAX_RETRY_DELAY: float = float(os.getenv("MINIMAX_RETRY_DELAY", "1.0"))
+
     # Fallback chain configuration
     # General fallback chain (backward compatibility)
     FALLBACK_CHAIN: List[str] = [
         name.strip()
         for name in os.getenv(
-            "PROVIDER_FALLBACK_CHAIN", "google,deepl,openai,ollama,openrouter"
+            "PROVIDER_FALLBACK_CHAIN", "google,deepl,deepseek,minimax,openai,ollama,openrouter"
         ).split(",")
         if name.strip()
     ]
@@ -186,6 +205,18 @@ class ProvidersConfig:
                 base_url="https://openrouter.ai/api/v1",
                 model=cls.OPENROUTER_MODEL,
             ),
+            "deepseek": ProviderSettings(
+                enabled=cls.DEEPSEEK_ENABLED,
+                api_key=cls.DEEPSEEK_API_KEY if cls.DEEPSEEK_API_KEY else None,
+                base_url=cls.DEEPSEEK_BASE_URL,
+                model=cls.DEEPSEEK_MODEL,
+            ),
+            "minimax": ProviderSettings(
+                enabled=cls.MINIMAX_ENABLED,
+                api_key=cls.MINIMAX_API_KEY if cls.MINIMAX_API_KEY else None,
+                base_url=cls.MINIMAX_BASE_URL,
+                model=cls.MINIMAX_MODEL,
+            ),
         }
         return settings_map.get(provider_name.lower(), ProviderSettings())
 
@@ -206,7 +237,7 @@ class ProvidersConfig:
             return False
 
         # Providers requiring API keys
-        providers_requiring_key = {"deepl", "openai", "openrouter", "google_cloud"}
+        providers_requiring_key = {"deepl", "openai", "openrouter", "google_cloud", "deepseek", "minimax"}
 
         if provider_name.lower() in providers_requiring_key:
             return bool(settings.api_key)