[FEATURE] Add tool_name to PreToolUse/PostToolUse hook events

Question

### Problem

Hook events for PreToolUse/PostToolUse don't include which tool is being used. To get this info, I have to parse CLAUDE_TOOL_INPUT env var.

### Proposal

Add tool_name field:
```json
{
  "hook_event_type": "PreToolUse",
  "tool_name": "Bash",
  "session_id": "xxx"
}
```

### Use Case

My monitoring app could show "Executing Bash" or "Edit pending":
https://github.com/usedhonda/cc-status-bar