Summary

When running a command prefix like cake cache (where cache itself is not a command but has subcommands like cache clear), show help for all commands with that prefix instead of showing an unhelpful "Did you mean" error message.

Before:

$ bin/cake cache
Unknown command `cake cache`. Did you mean: `cache clear`?

Other valid choices:

- help
- cache list
...

After:

$ bin/cake cache
Current Paths:
...

Available Commands:

cakephp:
 - cache clear
   └──────────── Clear all data in a single cache engine
 - cache list
   └──────────── Show a list of configured caches

To run a command, type `cake command_name [args|options]`
To get help on a specific command, type `cake command_name --help`

This improves discoverability of subcommands when users know the prefix but not the exact subcommand name.

Changes

• CommandRunner: Detect when a command prefix has subcommands and redirect to help with that prefix as filter
• HelpCommand: Add command argument to filter commands by prefix

Extracted bugfix from #19092 (separated from UI feature changes) for now to fast track the fixes while still discussing the UI changes.