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/websocket-auth/src/lib.rs

@@ -444,7 +444,9 @@ fn sha256_digest_arg(flag_name: &str, value: &str) -> anyhow::Result<[u8; 32]> {
     }
 
     let mut digest = [0u8; 32];
-    for (index, pair) in trimmed.as_bytes().chunks_exact(2).enumerate() {
+    const HEX_DIGITS_PER_BYTE: usize = 2;
+    let (pairs, _) = trimmed.as_bytes().as_chunks::<HEX_DIGITS_PER_BYTE>();
+    for (index, pair) in pairs.iter().enumerate() {
         let high = hex_nibble(flag_name, pair[0])?;
         let low = hex_nibble(flag_name, pair[1])?;
         digest[index] = (high << 4) | low;