Dockerize Django app with dev/beta/prod env config and uv.

Replace hardcoded settings with environment-driven config, add Docker
compose for local and production deploys, migrate from pip to uv, and
split Gitea workflows so PRs run tests only while master pushes deploy.

.gitea/workflows/ci.yml

@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  pull_request:
+    branches: [master]
+
+jobs:
+  test:
+    runs-on: self-hosted
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install uv
+        run: |
+          curl -LsSf https://astral.sh/uv/install.sh | sh
+          echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+
+      - name: Install dependencies
+        run: uv sync --frozen
+
+      - name: Run unit tests
+        env:
+          DJANGO_ENV: dev
+          DJANGO_SECRET_KEY: test-secret-key
+        run: |
+          cd company_site
+          uv run python manage.py test

.gitea/workflows/deploy.yml

@@ -1,5 +1,6 @@
 name: Deploy Company Site
 
+# Deploy pipeline runs only on pushes to master (never on pull requests).
 on:
   workflow_run:
     workflows: [Unit Tests]
@@ -7,9 +8,52 @@ on:
     branches: [master]
 
 jobs:
+  test:
+    runs-on: self-hosted
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install uv
+        run: |
+          curl -LsSf https://astral.sh/uv/install.sh | sh
+          echo "$HOME/.local/bin" >> "$GITHUB_PATH"
+
+      - name: Install dependencies
+        run: uv sync --frozen
+
+      - name: Run unit tests
+        env:
+          DJANGO_ENV: dev
+          DJANGO_SECRET_KEY: test-secret-key
+        run: |
+          cd company_site
+          uv run python manage.py test
+
+  docker:
+    runs-on: self-hosted
+    needs: test
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Build Docker image
+        run: docker compose build
+
+      - name: Run containerized tests
+        run: |
+          docker compose up -d db
+          docker compose run --rm --entrypoint "" \
+            -e DJANGO_ENV=dev \
+            -e DJANGO_SECRET_KEY=test-secret-key \
+            -e DATABASE_URL=postgres://company_site:company_site@db:5432/company_site \
+            web uv run python manage.py test
+          docker compose down
+
   deploy:
     if: gitea.event.workflow_run.conclusion == 'success' && gitea.event.workflow_run.event == 'push'
     runs-on: self-hosted
+    needs: [test, docker]
     steps:
       - name: Checkout
         uses: actions/checkout@v4