Upgrade the Rust toolchain to 1.99.1 (#61205)

## What changed

- Update the workspace, Bazel toolchain and lockfile, CI and release workflows, and Windows setup script from Rust `1.95.0` to `1.99.1`.
- Adapt Rust code to the updated toolchain and Clippy lints, including `try_update` for atomics, `as_chunks` for fixed-size slices, and targeted allowances for generated tonic services.
- Refresh the halfwidth sound mark rendering snapshot to use literal characters in debug output.

GitOrigin-RevId: 5852029f687436dc814c2bca68141ee1f4a67d49

codex-rs/code-mode-protocol/src/grpc/mod.rs

@@ -1,3 +1,5 @@
+#![allow(clippy::double_must_use)] // Emitted by async_trait in the generated tonic service.
+
 #[cfg(codex_bazel)]
 pub use code_mode_proto::codex::code_mode::v1::*;