Lock dependencies and python-version with uv

Locking is super important if you want to reproduce a certain state of
the package, as has been the case for wpull these last few years.

And provide a direnv integration to attach to the virtualenv.

Author: mweinelt

.envrc

@@ -0,0 +1,20 @@
+# https://github.com/direnv/direnv/pull/1352
+layout_uv() {
+  # Watch the uv configuration file for changes
+  watch_file .python-version pyproject.toml uv.lock
+
+  # Use --frozen so that direnv entry does not change the lock contents. This
+  # can fail if the lock file is badly out of sync, but it'll report that to the
+  # user and the resolution is obvious.
+  uv sync --frozen || true
+
+  # activate the virtualenv after syncing; this puts the newly-installed
+  # binaries on PATH.
+  venv_path="$(expand_path "${UV_PROJECT_ENVIRONMENT:-.venv}")"
+  if [[ -e $venv_path ]]; then
+    # shellcheck source=/dev/null
+    source "$venv_path/bin/activate"
+  fi
+}
+
+layout_uv

.python-version

@@ -0,0 +1 @@
+3.9.23