All tools now receive arguments as a JSON object on stdin instead of
positional CLI args. Each tool declares its schema via # args_json:
header comment.
New shared helpers:
- _lib/args.py: Python parse_args() -> Args with require/get/get_bool/etc
- _lib/args.sh: Bash arg_require/arg_get/arg_bool via jq
Removed denote_view (unused).
Updated WRITING_TOOLS.md to document the new contract.
Levi Neely