Fix Railway Nixpacks Python path

Author: Surya2Developer

nixpacks.toml

@@ -4,8 +4,8 @@ nixPkgs = ["python312Full"]
 # Use the default Python install behavior but ensure we use the right requirements file
 [phases.install]
 cmds = [
-    "python -m pip install --upgrade pip",
-    "python -m pip install -r backend/requirements.txt"
+    "/opt/venv/bin/python -m pip install --upgrade pip",
+    "/opt/venv/bin/python -m pip install -r backend/requirements.txt"
 ]
 
 
@@ -17,7 +17,7 @@ cmds = [
 
 [start]
 # Run directly from the root directory since we copied the files there
-cmd = "uvicorn main:app --host 0.0.0.0 --port $PORT"
+cmd = "/opt/venv/bin/uvicorn main:app --host 0.0.0.0 --port $PORT"
 
 [variables]
 PYTHONPATH = "/app"