Add ruby-rbs-sys Rust crate with FFI bindings for RBS parser

This establishes the foundation for using RBS functionality from Rust.

- Generated FFI bindings via bindgen from RBS C headers
- Set up build configuration to link with the RBS library
- Added initial tests for basic functionality (constant pool, parser)
- Configured workspace structure in rust/Cargo.toml

The -sys crate follows Rust conventions for FFI bindings, keeping raw
unsafe bindings separate from future safe API wrappers.

Future commits will add a separate safe wrapper crate on top of these
bindings.

Author: alexcrocha

.github/workflows/rust.yml

@@ -0,0 +1,76 @@
+name: Rust
+
+on:
+  push:
+    branches:
+      - master
+    paths:
+      - ".github/workflows/rust.yml"
+      - "rust/**"
+      - "include/**"
+      - "src/**"
+  pull_request:
+    paths:
+      - ".github/workflows/rust.yml"
+      - "rust/**"
+      - "include/**"
+      - "src/**"
+
+env:
+  RUSTFLAGS: "-D warnings"
+
+jobs:
+  test:
+    name: cargo:test
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust tools
+        run: |
+          rustup update --no-self-update stable
+          rustup default stable
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            rust/target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('rust/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-
+      - name: Run tests
+        run: |
+          cd rust
+          cargo test --verbose
+
+  lint:
+    name: cargo:lint
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install Rust tools
+        run: |
+          rustup update --no-self-update stable
+          rustup default stable
+          rustup component add --toolchain stable clippy rustfmt
+      - uses: actions/cache@v4
+        with:
+          path: |
+            ~/.cargo/registry
+            ~/.cargo/git
+            rust/target
+          key: ${{ runner.os }}-cargo-${{ hashFiles('rust/Cargo.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-cargo-
+      - name: Check formatting
+        run: |
+          cd rust
+          cargo fmt --check
+      - name: Run clippy
+        run: |
+          cd rust
+          cargo clippy

rust/.gitignore

@@ -0,0 +1 @@
+/target/

rust/Cargo.lock

@@ -0,0 +1,6 @@
+[workspace]
+members = [
+  "ruby-rbs-sys",
+]
+
+resolver = "3"

rust/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "ruby-rbs-sys"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+doctest = false
+
+[build-dependencies]
+bindgen = "0.72.0"
+cc = "1.2.29"