Creates local/scripts/TOOLS.md as a companion to HOOKS.md,
listing only the 10 build-system operator tools (excluding the
~120 test scripts under local/scripts/).
Each tool has:
- One-line purpose
- Usage example
- All mode flags documented
The reference includes a call-tree showing which tools
run in build-preflight.sh vs pre-push-checks.sh.
Added README.md link to TOOLS.md in the Documentation section.
