ci: fmt under stable 1.96 to make rust-ci green (follow-up) (#47)

## Summary

Follow-up to the merged CI-green PR. With rust-ci now running, `cargo
fmt --all -- --check` fails on `main` under the CI toolchain (stable
rustfmt 1.96) — the toolchain-pin landed before the formatting fix. This
brings the Rust sources to rustfmt-clean so rust-ci goes green.

## Changes

- **Rust hygiene:** `cargo fmt` (`src/codegen/parser.rs`) so `cargo fmt
--all -- --check` passes under stable 1.96.

## RSR Quality Checklist

### Required
- [x] Tests pass (`cargo test --locked --all-targets`)
- [x] Code is formatted (`cargo fmt --all -- --check`)
- [x] Linter is clean (`cargo clippy --locked --all-targets -- -D
warnings`)
- [x] No banned language patterns
- [x] SPDX license headers present on modified files
- [x] No secrets, credentials, or `.env` files included

## Testing

Verified locally with the CI toolchain (rustc/clippy/rustfmt 1.96.0):
`cargo fmt --check`, `clippy -D warnings`, `cargo check --locked`,
`cargo test --locked` all pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---
_Generated by [Claude
Code](https://claude.ai/code/session_01A6PSzJWpRxtzGDjUCEh7Mx)_

---------

Co-authored-by: Claude <noreply@anthropic.com>

Author: hyperpolymath

src/codegen/parser.rs

@@ -488,7 +488,8 @@ mod tests {
 
     #[test]
     fn parse_c_function_simple() {
-        let contract = try_parse_c_function("int process_item(void* input, size_t len);").expect("TODO: handle error");
+        let contract = try_parse_c_function("int process_item(void* input, size_t len);")
+            .expect("TODO: handle error");
         assert_eq!(contract.name, "process_item");
         assert_eq!(contract.return_type, "Int");
         assert_eq!(contract.params.len(), 2);
@@ -503,8 +504,8 @@ mod tests {
 
     #[test]
     fn parse_rpc_method() {
-        let contract =
-            try_parse_rpc("rpc GetUser (GetUserRequest) returns (UserResponse);").expect("TODO: handle error");
+        let contract = try_parse_rpc("rpc GetUser (GetUserRequest) returns (UserResponse);")
+            .expect("TODO: handle error");
         assert_eq!(contract.name, "GetUser");
         assert_eq!(contract.params[0].type_name, "GetUserRequest");
         assert_eq!(contract.return_type, "UserResponse");