Add a run menu (#32505)

As part of this I refactored the logic that enabled/disabled actions in
the debugger to happen at action registration time instead of using
command palette filters. This allows the menu to grey out actions correctly.

Release Notes:

- Add a "Run" menu to contain tasks and debugger

assets/settings/initial_tasks.json

@@ -1,4 +1,4 @@
-// Static tasks configuration.
+// Project tasks configuration. See https://zed.dev/docs/tasks for documentation.
 //
 // Example:
 [