Fix API key file loading logic

2_backend_llm/app/config.py

@@ -21,13 +21,29 @@ def _load_api_key_from_file(key_name: str) -> str | None:
     """Load API key from file if environment variable is not set."""
     # Try to find the key file in project root
     project_root = Path(__file__).resolve().parent.parent.parent
-    key_file = project_root / f"{key_name.lower()}.txt"
     
-    if key_file.exists():
-        try:
-            return key_file.read_text().strip()
-        except Exception:
-            pass
+    # Try different file name formats
+    possible_names = [
+        f"{key_name.lower()}.txt",  # gemini_api_key.txt
+        f"{key_name.replace('_', '').lower()}.txt",  # gemini apikey.txt
+    ]
+    
+    for filename in possible_names:
+        key_file = project_root / filename
+        if key_file.exists():
+            try:
+                return key_file.read_text().strip()
+            except Exception:
+                pass
+    
+    # Also try gemini_api_key.txt specifically (the file we created)
+    if key_name == "GEMINI_API_KEY":
+        gemini_file = project_root / "gemini_api_key.txt"
+        if gemini_file.exists():
+            try:
+                return gemini_file.read_text().strip()
+            except Exception:
+                pass
     
     return None