feat(deploy): add declarative installation workflow

.gitea/workflows/deployment-installer.yml

@@ -0,0 +1,30 @@
+name: Deployment Installer
+
+on:
+  pull_request:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  deployment-installer:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5
+        with:
+          path: govoplan
+      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065
+        with:
+          python-version: "3.12"
+      - name: Compile deployment tooling
+        working-directory: govoplan
+        run: python -m py_compile tools/deployment/govoplan-deploy.py tools/deployment/govoplan_deploy/*.py
+      - name: Test declarative deployment bundle
+        working-directory: govoplan
+        run: python -m unittest -v tests.test_deployment_installer
+      - name: Build single-file deployer artifact
+        working-directory: govoplan
+        run: |
+          python tools/deployment/build-deployer-zipapp.py --output /tmp/govoplan-deploy.pyz
+          python /tmp/govoplan-deploy.pyz --help