Hook events: PreToolUse split into classic vs. new, and two new synchronous hook events added

The logic that warns when a hook blocks a turn now specifically matches classic.PreToolUse rather than a plain PreToolUse event, implying PreToolUse (a hook that runs before a tool call executes and can block it) now has both a classic and a newer variant. Two new events, command.run and command.describe, have also been added to the set of hook events where submitting mid-hook will wait on the current turn to finish.