Add Example 6 showing how to create a hook that reports context/token
usage after each Claude response:
- Python script reads transcript_path to access conversation history
- Estimates tokens using ~4 chars/token heuristic
- Outputs one-line report: "Context: ~45k/200k tokens (77% remaining)"
- Documents both Stop and UserPromptSubmit hook configurations
- Explains limitations (estimate vs exact /context command)