ci: add MSRV (1.80) and beta channel testing via matrix

Matrix strategy with conditional steps:
- MSRV (1.80): build + test only (no clippy - lints evolve)
- stable: full checks on all platforms (ubuntu/macos/windows)
- beta: clippy + test, allowed to fail (early warning)

Uses dtolnay/rust-toolchain@master with toolchain parameter for flexibility.

Author: 27Bslash6

.github/workflows/ci.yml

@@ -10,34 +10,55 @@ concurrency:
 
 jobs:
   test:
+    name: ${{ matrix.rust }} / ${{ matrix.os }}
     runs-on: ${{ matrix.os }}
+    continue-on-error: ${{ matrix.rust == 'beta' }}
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest, windows-latest]
+        # Full OS matrix for stable only; MSRV and beta on ubuntu only
+        include:
+          # MSRV - ensures we don't use newer Rust features
+          - rust: "1.80"
+            os: ubuntu-latest
+          # Stable - primary target, all platforms
+          - rust: stable
+            os: ubuntu-latest
+          - rust: stable
+            os: macos-latest
+          - rust: stable
+            os: windows-latest
+          # Beta - early warning (allowed to fail)
+          - rust: beta
+            os: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
 
       - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
+        uses: dtolnay/rust-toolchain@master
         with:
-          components: rustfmt, clippy
+          toolchain: ${{ matrix.rust }}
+          components: ${{ matrix.rust != '1.80' && 'rustfmt, clippy' || '' }}
 
       - name: Cache cargo registry
         uses: Swatinem/rust-cache@v2
         with:
           cache-all-crates: true
 
+      # Formatting and clippy only on stable (lints evolve between versions)
       - name: Check formatting
+        if: matrix.rust == 'stable'
         run: cargo fmt --check
 
       - name: Run clippy
+        if: matrix.rust != '1.80'
         run: cargo clippy --all-features -- -D warnings
 
       - name: Run tests (all features)
         run: cargo test --all-features
 
       - name: Run FFI tests
+        if: matrix.rust == 'stable'
         run: cargo test --features ffi
 
   security: