Refactor: Implement no_std and zero-copy API

.github/workflows/ci.yml

@@ -49,6 +49,21 @@ jobs:
           files: lcov.info
           fail_ci_if_error: true
 
+  no_std:
+    name: Build no_std (bare-metal)
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@v5
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: thumbv6m-none-eabi
+      - uses: Swatinem/rust-cache@v2
+      - name: Build no_std + no_alloc
+        run: cargo build --no-default-features --target thumbv6m-none-eabi
+      - name: Build no_std + alloc
+        run: cargo build --no-default-features --features alloc --target thumbv6m-none-eabi
+
   lint:
     name: Run Clippy
     runs-on: ubuntu-latest
@@ -59,6 +74,8 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - run: rustup component add clippy
       - run: cargo clippy --all-features
+      - run: cargo clippy --no-default-features
+      - run: cargo clippy --no-default-features --features alloc
 
   format:
     name: Run Cargo Format