chore: add CI/CD pipeline for Gitea deployment

- Add .gitea/workflows/build.yml for tag-triggered builds
- Add Dockerfile for containerized deployment (port 8086)
- Add .dockerignore to keep image lean
- Add CHANGELOG.md following Keep a Changelog format
- Update AGENTS.md with deployment verification URL

Build pipeline:
1. Create Gitea release on v* tag
2. Build and push Docker image to git.schweitz.internal
3. Trigger Watchtower for automatic deployment

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

.gitea/workflows/build.yml

@@ -0,0 +1,46 @@
+name: Build and Push
+
+on:
+  push:
+    tags:
+      - 'v*'
+
+jobs:
+  release:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Create Gitea Release
+        run: |
+          curl -sf -X POST \
+            -H "Authorization: token ${{ secrets.GITHUB_TOKEN }}" \
+            -H "Content-Type: application/json" \
+            -d '{"tag_name": "${{ github.ref_name }}", "name": "Release ${{ github.ref_name }}", "body": "Automated release for ${{ github.ref_name }}"}' \
+            "${{ github.server_url }}/api/v1/repos/${{ github.repository }}/releases"
+
+  build:
+    runs-on: ubuntu-latest
+    needs: release
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Login to Gitea Registry
+        uses: docker/login-action@v3
+        with:
+          registry: git.schweitz.internal
+          username: ${{ secrets.REGISTRY_USER }}
+          password: ${{ secrets.REGISTRY_PASSWORD }}
+
+      - name: Build and push
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: |
+            git.schweitz.internal/jpmschweitzer/webber:latest
+            git.schweitz.internal/jpmschweitzer/webber:${{ github.ref_name }}
+
+      - name: Trigger Watchtower update
+        if: success()
+        run: |
+          curl -sf -H "Authorization: Bearer ${{ secrets.WATCHTOWER_TOKEN }}" \
+            http://watchtower:8080/v1/update