feat(skills): add style review workflow

src/skills/style/rust/rules/files.md

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+# File rules
+
+## Avoid generic Rust file names
+
+### Rule
+
+Do not name Rust source files `lib.rs` or `main.rs`.
+Name library crate root files after the crate they define.
+Name binary crate root files after the binary they define, or use a `_main.rs` suffix.
+Set explicit Cargo paths and Bazel `srcs` when needed.
+
+### Rationale
+
+Generic root names make file search results and review context less clear.
+Descriptive file names show which crate or binary owns the code.
+
+## Keep Rust tests in separate files
+
+### Rule
+
+Put Rust tests in separate `*_test.rs` files.
+Name each test file after the Rust source file or crate root that it tests.
+Do not use generic test file names such as `lib_test.rs` or `main_test.rs`.
+Do not add inline `#[cfg(test)]` modules.
+
+### Rationale
+
+Separate test files keep production modules focused and match the repository's Bazel test layout.