`SetCVar` and `RegisterCVar` now read their arguments as the reference's bindings do (`0x488c10`, `0x488b00`):
- a number is stored as Lua's `%.14g` text (`luaV_tostring` `0x6f7c80`), so the stock Sound slider's 0.4 stores `"0.40000000596046"`;
- a value with no string form (nil, absent, boolean, table) stores `"0"` (`0x488c98`, `0x488b6f`), so unticking a stock Sound options box no longer raises and music can be switched off there;
- the reference's usage texts (`0x84235c`, `0x8422e8`);
- `realmList`, `realmName` and `scriptMemory` are read-only to Lua `SetCVar` in the world (`0x48f566`-`0x48f584`), and host writes still land;
- `CVAR_UPDATE` fires inside the call for every string token, changed or not (`0x488cad`-`0x488cd5`, `SignalEvent2` `0x703f50`).
Verified: 7 new VM tests, a stock Sound window test off the chain and a world-entry read-only test, each failing with the change undone; `scripts/gates.sh` green. Built on macOS; no platform seam touched.
Fixes#167Fixes#139Fixes#547🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>