Establish native deterministic codegen framework (#45)

.gitea/workflows/codegen.yml

@@ -0,0 +1,31 @@
+name: Native code generation
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  deterministic:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy,rustfmt
+      - name: Test diagnostics and byte-identical generation
+        run: cargo test -p libremetaverse-codegen
+      - name: Verify vendored hashes and checked-in output
+        run: cargo run -p libremetaverse-codegen -- check
+      - name: Regenerate twice without reference checkout access
+        run: |
+          cargo run -p libremetaverse-codegen -- generate
+          cargo run -p libremetaverse-codegen -- generate
+          git diff --exit-code -- codegen/generated
+      - name: Lint native generator
+        run: cargo clippy -p libremetaverse-codegen --all-targets -- -D warnings
+      - name: Prove normal consumer build does not execute generation
+        run: cargo build -p libremetaverse --locked