fix: skip After hook when help is displayed on subcommand

[dearchap]

Summary

Fixes #2250 — when --help is passed to a subcommand, the parent command's After hook was firing even though the parent's Before hook was never called. This violates the expected invariant that After should only be called when Before was also called.

Root Cause

In command_run.go, the After hook is registered as a deferred call at line 227, before the subcommand dispatch (line 298) and the Before chain (line 312). When a subcommand receives --help, the subcommand's run() returns early at the help check (line 205), never reaching the Before chain. The parent's deferred After then fires without the corresponding Before.

Fix

Track help invocation via a helpShownKey in the context. When --help is detected (both in the success path and the parse-error-then-help path), set the key in the context before returning. The deferred After hook checks this key and returns early if help was the reason for early exit.

Tests Added

• TestCommand_AfterNotCalledOnSubcommandHelp — verifies After is NOT called when app sub --help is used
• TestCommand_AfterStillCalledOnNormalSubcommand — verifies After IS called for normal app sub execution

[abitrolly]

I don't know. Maybe there should be a separate helpMode traversal|walk which is (docu|imple)mented as not triggering any hooks at all?

[meatballhat]

I tend to agree with @abitrolly but given that this is internal I think a more tidy implementation could be in a follow up.