feat: add OpencodeGo AI provider (deepseek-v4-flash) as primary, existing providers as fallback

backend/app/ai/router.py

@@ -1,6 +1,6 @@
 from typing import Dict, Any, Optional, List
 from app.ai.base import AIProvider
-from app.ai.providers import OpenAIProvider, ClaudeProvider, DeepLProvider, LocalProvider, SparkProvider, SensenovaProvider
+from app.ai.providers import OpenAIProvider, ClaudeProvider, DeepLProvider, LocalProvider, SparkProvider, SensenovaProvider, OpencodeGoProvider
 from app.config import settings
 from app.ai.trade_corpus import TradeCorpus
 import logging
@@ -34,6 +34,17 @@ class AIRouter:
             except Exception as e:
                 logger.warning(f"Sensenova init failed: {e}")
 
+        if settings.OPENCODE_GO_API_KEY:
+            try:
+                self.providers["opencode_go"] = OpencodeGoProvider(
+                    api_key=settings.OPENCODE_GO_API_KEY,
+                    model=settings.OPENCODE_GO_MODEL,
+                    base_url=settings.OPENCODE_GO_BASE_URL,
+                )
+                logger.info("OpencodeGo provider ready")
+            except Exception as e:
+                logger.warning(f"OpencodeGo init failed: {e}")
+
         if settings.ANTHROPIC_API_KEY:
             try:
                 self.providers["anthropic"] = ClaudeProvider(api_key=settings.ANTHROPIC_API_KEY)