doc: clarification around running outside docker

Author: wjohnsto

Makefile

@@ -26,4 +26,5 @@ lock: install
 	@uv lock
 
 clean:
-	@rm -rf .venv/ .mypy_cache/ .ruff_cache/
+	@rm -rf .venv/ .mypy_cache/ .ruff_cache/ .pytest_cache/
+	@find . -type d -name __pycache__ -exec rm -r {} \+

README.md

@@ -58,7 +58,7 @@ These tests setup and teardown on their own. You can modify them if you want to
 To run the development server outside of docker:
 
 ```bash
-make dev
+make install && source .venv/bin/activate && make dev
 ```
 
 ## Other Scripts