Pin the Rust toolchain to 1.95.0 (#57373)

## What changed

- Replace Rust `1.99.1` pins with `1.95.0` across Cargo, Bazel, CI, release workflows, and Windows setup, and update the Bazel lockfile.
- Adjust Rust APIs, borrowing, and lint-related code for the pinned toolchain, and box MCP tool dispatch to bound compiler async-layout query depth.
- Update the halfwidth sound mark snapshot and allow optional symbol hash suffixes in the code mode host package smoke test.

GitOrigin-RevId: 75460c3d0465dc601811e619bce373a4f7ff2912

codex-rs/exec-server-protocol/src/protocol.rs

@@ -268,7 +268,7 @@ impl EnvironmentInfo {
             if let Some(path) = std::env::var_os(name)
                 .filter(|path| !path.is_empty())
                 .filter(|path| cfg!(unix) || std::path::Path::new(path).is_absolute())
-                .and_then(normalize_temp_path)
+                .and_then(&normalize_temp_path)
                 && !temporary_directories.contains(&path)
             {
                 temporary_directories.push(path);