Enhancement: Add a field to store the failure reason for Commands

[Rucha0901]

What would you like to be added:
A status_reason field to the Command protobuf message to store the reason for a command failure.

Why is this needed:
Currently, when a command fails, its status is updated to COMMAND_FAILED but there is no dedicated field to record exactly why it failed. This makes debugging difficult for users. Adding a status_reason field will resolve the TODO in pkg/model/command.proto and provide better error tracking.

[armistcxy]

Thank you @Rucha0901, I think this maybe a good catch

[armistcxy]

More context for this issue:

• Command is an instruction that control plane sends to piped to execute some actions
• Lack of failed reason makes user confuse
• Errors are only logged in server
• Example of usecase triggering command ?: When running pipectl application sync