Add Gitea Actions workflow to build Windows EXE

Builds on every push to main and on release publication.
Uploads the artifact on every build; attaches es24n_conf.exe
directly to any published release.

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

.gitea/workflows/build.yml

@@ -0,0 +1,43 @@
+name: Build Windows EXE
+
+on:
+  push:
+    branches: [main]
+  release:
+    types: [published]
+
+jobs:
+  build:
+    runs-on: windows
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install dependencies
+        run: pip install -r requirements.txt
+
+      - name: Build EXE
+        run: pyinstaller es24n_conf.spec
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: es24n_conf-windows
+          path: dist/es24n_conf.exe
+
+      - name: Attach EXE to release
+        if: github.event_name == 'release'
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ github.event.release.upload_url }}
+          asset_path: dist/es24n_conf.exe
+          asset_name: es24n_conf.exe
+          asset_content_type: application/octet-stream