Fix panic in debug probe

[dvush]

before:

./builder-playground debug probe

goroutine 1 [running]:
main.init.func2(0xc00005f900?, {0x311fe20?, 0x4?, 0x174b889?})
	/home/dvush/flashbots/code/builder-playground/main.go:145 +0x105
github.com/spf13/cobra.(*Command).execute(0x2667c20, {0x311fe20, 0x0, 0x0})
	/home/dvush/.local/share/go/pkg/mod/github.com/spf13/[email protected]/command.go:1015 +0xb02
github.com/spf13/cobra.(*Command).ExecuteC(0x2666e60)
	/home/dvush/.local/share/go/pkg/mod/github.com/spf13/[email protected]/command.go:1148 +0x465
github.com/spf13/cobra.(*Command).Execute(...)
	/home/dvush/.local/share/go/pkg/mod/github.com/spf13/[email protected]/command.go:1071
main.main()
	/home/dvush/flashbots/code/builder-playground/main.go:320 +0xa49

after:

Error: accepts 1 arg(s), received 0
Usage:
  playground debug probe <service> [flags]

Flags:
  -h, --help   help for probe

accepts 1 arg(s), received 0

[Copilot]

Pull request overview

This PR fixes a panic that occurred when running the debug probe command without the required argument. The fix adds proper argument validation and usage documentation.

• Adds cobra.ExactArgs(1) validation to prevent the panic when no arguments are provided
• Adds descriptive Use, Short, and Long fields to improve command documentation
• Sets cmd.SilenceUsage = true to suppress usage output for internal errors (not validation errors)

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