docs: use uv pip install in development setup instructions

README.md

@@ -124,7 +124,7 @@ git clone https://github.com/bkrabach/muxplex
 cd muxplex
 
 # Install with dev dependencies
-pip install -e ".[dev]"
+uv pip install -e ".[dev]"
 ```
 
 ### Run the server

requirements.txt

@@ -1,6 +1,6 @@
 # Dependencies are now managed in pyproject.toml.
 # Install runtime + dev dependencies with:
 #
-#   pip install -e ".[dev]"
+#   uv pip install -e ".[dev]"
 #
 # This file is kept for historical reference only and is no longer authoritative.