Wrap every builtin tool with withMeta({set, mutating}) at its definition
site (src/tool-utils.ts). TOOL_SETS and MUTATING_TOOLS are now derived
via setsFrom/mutatingNames rather than hand-lists, so a new write cannot
be added ungated by forgetting a parallel list. Permission defaults now
cover the 5 extra mutating line-edit tools. Test suite covers coverage,
derived-equality, and mutating consistency (test/tool-derive.test.ts).
