chore(ci): adicionar workflow de release automático

Cria tag e GitHub Release a partir da versão do package.json e da
entrada correspondente no CHANGELOG.md ao fazer push na branch main.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.github/workflows/release.yml

@@ -0,0 +1,59 @@
+name: Release
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Read version from package.json
+        id: version
+        run: |
+          VERSION=$(jq -r '.version' package.json)
+          echo "value=$VERSION" >> $GITHUB_OUTPUT
+          echo "tag=v$VERSION" >> $GITHUB_OUTPUT
+
+      - name: Check if tag already exists
+        id: tag_check
+        run: |
+          if git ls-remote --tags origin "refs/tags/v${{ steps.version.outputs.value }}" | grep -q .; then
+            echo "exists=true" >> $GITHUB_OUTPUT
+          else
+            echo "exists=false" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Extract changelog for this version
+        if: steps.tag_check.outputs.exists == 'false'
+        id: changelog
+        run: |
+          VERSION="${{ steps.version.outputs.value }}"
+          # Extrai o bloco entre ## [X.Y.Z] e o próximo ## [
+          NOTES=$(awk "/^## \[$VERSION\]/{found=1; next} found && /^## \[/{exit} found{print}" CHANGELOG.md)
+          # Remove linhas em branco do início e fim
+          NOTES=$(echo "$NOTES" | sed '/./,$!d' | sed -e :a -e '/^\n*$/{$d;N;ba}')
+          {
+            echo "notes<<EOF"
+            echo "$NOTES"
+            echo "EOF"
+          } >> $GITHUB_OUTPUT
+
+      - name: Create tag and GitHub Release
+        if: steps.tag_check.outputs.exists == 'false'
+        uses: softprops/action-gh-release@v2
+        with:
+          tag_name: ${{ steps.version.outputs.tag }}
+          name: ${{ steps.version.outputs.tag }}
+          body: ${{ steps.changelog.outputs.notes }}
+          draft: false
+          prerelease: false