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/codex-mcp/src/connection_manager/startup.rs

@@ -42,13 +42,14 @@ pub(super) async fn emit_update(
     submit_id: &str,
     tx_event: &Sender<Event>,
     update: McpStartupUpdateEvent,
-) -> Result<(), async_channel::SendError<Event>> {
+) -> Result<(), Box<async_channel::SendError<Event>>> {
     tx_event
         .send(Event {
             id: submit_id.to_string(),
             msg: EventMsg::McpStartupUpdate(update),
         })
         .await
+        .map_err(Box::new)
 }
 
 pub(super) fn mcp_startup_failure_reason(