Update PEP 723 lockfile in uv add --script (#10145)

## Summary

`uv add --script main.py anyio` will now update the lockfile, _if_ it
already exists. (If no such lockfile exists, the behavior is unchanged.)

crates/uv-cli/src/lib.rs

@@ -3257,7 +3257,12 @@ pub struct AddArgs {
     /// a new one will be created and added to the script. When executed via `uv run`,
     /// uv will create a temporary environment for the script with all inline
     /// dependencies installed.
-    #[arg(long, conflicts_with = "dev", conflicts_with = "optional")]
+    #[arg(
+        long,
+        conflicts_with = "dev",
+        conflicts_with = "optional",
+        conflicts_with = "package"
+    )]
     pub script: Option<PathBuf>,
 
     /// The Python interpreter to use for resolving and syncing.