Add corex library with resource-aware execution primitives

- Implement CI workflow for formatting, linting, testing, and documentation checks.
- Create publish workflow for automated publishing to crates.io.
- Add .gitignore to exclude build artifacts and editor files.
- Define Cargo.toml for corex and corex-core with dependencies and metadata.
- Add README.md files for corex and corex-core with usage instructions and licensing.
- Implement core execution primitives: spawn_io, compute, and spawn_bg with panic isolation.
- Establish global engine context for resource management based on logical CPU cores.
- Introduce error handling for compute panics.

.github/workflows/ci.yml

@@ -0,0 +1,86 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  fmt:
+    name: Rustfmt
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: rustfmt
+      - run: cargo fmt --all --check
+
+  clippy:
+    name: Clippy
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy
+      - name: Clippy (all features)
+        run: cargo clippy --workspace --all-features -- -D warnings
+      - name: Clippy (no default features)
+        run: cargo clippy --workspace --no-default-features -- -D warnings
+
+  test-matrix:
+    name: Test (${{ matrix.name }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: default features
+            flags: ""
+          - name: all features
+            flags: "--all-features"
+          - name: io only
+            flags: "--no-default-features --features io"
+          - name: compute only
+            flags: "--no-default-features --features compute"
+          - name: bg only
+            flags: "--no-default-features --features bg"
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - name: Build
+        run: cargo build --workspace ${{ matrix.flags }}
+      - name: Test
+        run: cargo test --workspace ${{ matrix.flags }}
+
+  example:
+    name: Run example
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: cargo run --example main --features full
+
+  docs:
+    name: Docs check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: RUSTDOCFLAGS="-D warnings" cargo doc --workspace --all-features --no-deps
+
+  package:
+    name: Cargo package dry-run
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - name: Package corex-core
+        run: cargo package -p corex-core --no-verify
+      - name: Package corex
+        run: cargo package -p corex --no-verify

.github/workflows/publish.yml

@@ -0,0 +1,23 @@
+name: Publish to crates.io
+
+on:
+  push:
+    tags: ["v*.*.*"]
+
+jobs:
+  publish:
+    name: Publish
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - name: Publish corex-core
+        run: cargo publish -p corex-core --allow-dirty --no-verify
+        env:
+          CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
+      - name: Wait for crates.io indexing
+        run: sleep 30
+      - name: Publish corex
+        run: cargo publish -p corex --allow-dirty --no-verify
+        env:
+          CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}