[FEATURE] hook events for user shift-tab or commands.

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

If we could somehow have PostToolUse hooks for user events, that'd be great. One example is a user typing certain commands or entering plan mode with Shift-Tab.

More important issues to resolve first:
#15755

#16001

Proposed Solution

Post tool use events even for user-initiated behavior.

Alternative Solutions

_No response_

Priority

Medium - Would be very helpful

Feature Category

CLI commands and flags

Use Case Example

Plugins like plannotator

I can provide a retro UX and review cycle of plans if I understand when a plan was initiated.

Additional Context

_No response_