* 🔧 Bump Rust version of the devenv image to 1.99
* 🔧 Run the pinned Rust setup from the lint and format scripts
./build and ./test switch to the Rust version in render-wasm/_build_env
through setup, but ./lint did not, and formatting called cargo fmt
directly. In CI both ran on the devenv image's default toolchain.
Make ./lint run setup and add a ./fmt script that does the same, so all
render-wasm entry points use the pinned version. CI and scripts/ci now
call ./fmt instead of cargo fmt.
AI-assisted-by: claude-opus-5-5
