Support uv run -m foo to run a module (#7754)

## Summary

This is another attempt using `module: bool` instead of `module:
Option<String>` following #7322.
The original PR can't be reopened after a force-push to the branch, I've
created this new PR.

Resolves #6638

crates/uv-cli/src/lib.rs

@@ -2469,6 +2469,12 @@ pub struct RunArgs {
     #[arg(long, overrides_with("dev"))]
     pub no_dev: bool,
 
+    /// Run a Python module.
+    ///
+    /// Equivalent to `python -m <module>`.
+    #[arg(short, long)]
+    pub module: bool,
+
     /// Omit non-development dependencies.
     ///
     /// The project itself will also be omitted.
@@ -2495,7 +2501,7 @@ pub struct RunArgs {
     #[arg(long)]
     pub with: Vec<String>,
 
-    /// Run with the given packages installed as editables
+    /// Run with the given packages installed as editables.
     ///
     /// When used in a project, these dependencies will be layered on top of
     /// the project environment in a separate, ephemeral environment. These