infra: add UV_FROZEN to makefiles (#29642)

These are set in Github workflows, but forgot to add them to most
makefiles for convenience when developing locally.

`uv run` will automatically sync the lock file. Because many of our
development dependencies are local installs, it will pick up version
changes and update the lock file. Passing `--frozen` or setting this
environment variable disables the behavior.

libs/cli/Makefile

@@ -3,6 +3,9 @@
 # LINTING AND FORMATTING
 ######################
 
+.EXPORT_ALL_VARIABLES:
+UV_FROZEN = true
+
 # Define a variable for Python and notebook files.
 PYTHON_FILES=.
 MYPY_CACHE=.mypy_cache