docs(skills): add build style skill

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

@@ -1,39 +0,0 @@
-# Build rules
-
-## Use workspace dependency versions
-
-### Rule
-
-Declare Rust dependency versions in the repository root `Cargo.toml` under `[workspace.dependencies]`.
-Reference workspace dependencies from package `Cargo.toml` files with `workspace = true`.
-Do not declare dependency versions in package `Cargo.toml` files unless the operator explicitly requests a package-local version.
-Add package-local dependency features only when the feature set is specific to that package.
-
-### Rationale
-
-The repository has one Cargo workspace and one `Cargo.lock`.
-Centralized dependency versions keep package manifests consistent with the workspace lockfile.
-
-## Declare Rust tests in Bazel
-
-### Rule
-
-Declare Rust test files in the nearest Bazel `BUILD` file with `rust_test`.
-Do not add `[[test]]` entries to `Cargo.toml` unless the operator explicitly requests Cargo test declarations.
-
-### Rationale
-
-Bazel is the source of truth for Rust test targets in this repository.
-Keeping test declarations in Bazel avoids duplicate test target lists.
-
-## Use one source input style per `rust_test`
-
-### Rule
-
-Do not set both `crate` and `srcs` on a `rust_test` target.
-Use exactly one input style for each Rust test target.
-
-### Rationale
-
-`rules_rust` rejects `rust_test` targets that set both `crate` and `srcs`.
-Keeping one input style per target makes the test declaration valid and unambiguous.