ci: make CI genuinely green — rust-ci toolchain pin + fmt/clippy (#57)

## Summary

Make CI genuinely green. The shared rust-ci pin on `main` predates
standards#439, so the SHA-pinned `dtolnay/rust-toolchain` step errors
out before the job runs. This bumps the pin so rust-ci actually runs,
and brings the Rust sources to fmt + clippy(`-D warnings`) clean under
the CI toolchain (stable 1.96).

## Changes

- **rust-ci:** bump `rust-ci-reusable.yml` pin `d135b05` → `8dc2bf0`
(current `standards` HEAD; includes #439 toolchain fix + #441/#442).
- **Rust hygiene:** `cargo fmt` + `clippy --fix`
(`src/codegen/accessibility.rs`, `src/codegen/i18n.rs`) so `cargo fmt
--all -- --check` and `cargo clippy --locked --all-targets -- -D
warnings` pass.

## 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

.github/workflows/rust-ci.yml

@@ -14,4 +14,4 @@ permissions:
 
 jobs:
   rust-ci:
-    uses: hyperpolymath/standards/.github/workflows/rust-ci-reusable.yml@d135b05bfc647d0c0fbfedc7e80f37ea50f49236
+    uses: hyperpolymath/standards/.github/workflows/rust-ci-reusable.yml@8dc2bf039d1ff0372d650895c46bea7fbaec68ff

src/codegen/accessibility.rs

@@ -356,7 +356,8 @@ mod tests {
             criterion: "1.1.1".to_string(),
         }];
 
-        let report = generate_accessibility_report(&manifest, &violations).expect("TODO: handle error");
+        let report =
+            generate_accessibility_report(&manifest, &violations).expect("TODO: handle error");
         assert!(!report.passes); // should fail due to error-level violation
         assert_eq!(report.accessibility_violations_count, 1);
     }

src/codegen/i18n.rs

@@ -337,7 +337,8 @@ mod tests {
             context: None,
         }];
 
-        let files = generate_locale_files(&manifest, &strings, output_dir).expect("TODO: handle error");
+        let files =
+            generate_locale_files(&manifest, &strings, output_dir).expect("TODO: handle error");
         assert_eq!(files.len(), 2); // en-GB + fr-FR
 
         // Check that the default locale file has the value.