feat(HAI-077): add CI/CD workflows for PRs, releases, and manual testing

- Add CI workflow for pull requests and pushes with lint, test, and build steps
- Add release workflow for tagged versions with automated publishing
- Add manual test-release workflow for on-demand validation
- Add workflow validation tests and remove obsolete build/test files
- Update README with CI/CD documentation and badge references

.github/workflows/release.yml

@@ -0,0 +1,63 @@
+name: Release
+
+on:
+  push:
+    tags:
+      - "v*"
+
+permissions:
+  contents: write
+
+jobs:
+  release:
+    name: Build & Release
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+          cache: pnpm
+
+      - name: Install Bun
+        uses: oven-sh/setup-bun@v2
+
+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Build
+        run: pnpm build
+
+      - name: Build standalone binary
+        run: pnpm build:exe
+
+      - name: Rename binary with platform and arch
+        run: |
+          PLATFORM=$(uname -s | tr '[:upper:]' '[:lower:]')
+          ARCH=$(uname -m)
+          case "$ARCH" in
+            x86_64) ARCH="x64" ;;
+            aarch64) ARCH="arm64" ;;
+          esac
+          cp packages/cli/dist/hai packages/cli/dist/hai-${PLATFORM}-${ARCH}
+
+      - name: Generate checksums
+        run: |
+          cd packages/cli/dist
+          for file in hai-*; do
+            sha256sum "$file" > "${file}.sha256"
+          done
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          generate_release_notes: true
+          files: |
+            packages/cli/dist/hai-*