Let guides use uv for python patterns

docs/guides/parallelizing-work.mdx

@@ -263,7 +263,7 @@ restate-server
     ./gradlew -PmainClass=my.example.parallelizework.FanOutWorkerKt run
     ```
     ```shell Python
-    python parallelizework/app.py
+    uv run parallelizework/app.py
     ```
     ```shell Go
     go run ./src/parallelizework

docs/guides/sagas.mdx

@@ -321,7 +321,7 @@ Restate automatically retries transient failures (network hiccups, temporary out
     ```
 
     ```bash Python
-    python sagas/app.py
+    uv run sagas/app.py
     ```
 
     ```bash Go