ci: add CI and release workflows

- ci.yml: build/test on push and PR
- release.yml: cross-platform build with artifact upload on main push and manual trigger

🤖 Generated with [Claude Code](https://claude.ai/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: aster-void

.github/workflows/ci.yml

@@ -0,0 +1,25 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: cargo build
+
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: dtolnay/rust-toolchain@stable
+      - run: cargo test

.github/workflows/release.yml

@@ -0,0 +1,55 @@
+name: Release
+
+on:
+  push:
+    branches: [main]
+  workflow_dispatch:
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        include:
+          - os: ubuntu-latest
+            target: x86_64-unknown-linux-gnu
+            artifact: rollcron-linux-x86_64
+          - os: macos-latest
+            target: x86_64-apple-darwin
+            artifact: rollcron-macos-x86_64
+          - os: macos-latest
+            target: aarch64-apple-darwin
+            artifact: rollcron-macos-aarch64
+          - os: windows-latest
+            target: x86_64-pc-windows-msvc
+            artifact: rollcron-windows-x86_64.exe
+
+    runs-on: ${{ matrix.os }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.target }}
+
+      - name: Build
+        run: cargo build --release --target ${{ matrix.target }}
+
+      - name: Rename artifact (Unix)
+        if: runner.os != 'Windows'
+        run: mv target/${{ matrix.target }}/release/rollcron ${{ matrix.artifact }}
+
+      - name: Rename artifact (Windows)
+        if: runner.os == 'Windows'
+        run: mv target/${{ matrix.target }}/release/rollcron.exe ${{ matrix.artifact }}
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.artifact }}
+          path: ${{ matrix.artifact }}
+