feat(pos/facturapi): finalize Horux-to-Facturapi migration

- Normalize Facturapi key/org_id resolution (supports both cfdi_ prefixed
  tenant_config keys and short names used by invoicing_bp).
- Add CSD upload end-to-end (backend + frontend).
- Add helper scripts: setup_facturapi_orgs.py and check_facturapi_tenants.py.
- Add 20 unit tests with mocks (pos/tests/test_facturapi_service.py).
- Add CI workflow for lint + console tests on Python 3.11/3.13.
- Add pyproject.toml and requirements-dev.txt with ruff/pytest config.
- Update FASES_IMPLEMENTADAS.md with FASE 8 documentation.

Tests: 81 passing (61 console + 20 Facturapi).

.github/workflows/ci.yml

@@ -0,0 +1,67 @@
+name: CI
+
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+    branches: [main, master]
+
+jobs:
+  lint-and-test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python-version: ["3.11", "3.13"]
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt
+          pip install -r pos/requirements.txt
+          pip install -r requirements-dev.txt
+
+      - name: Determine changed Python files
+        id: changed
+        run: |
+          if [ "${{ github.event_name }}" = "pull_request" ]; then
+            BASE="${{ github.event.pull_request.base.sha }}"
+          else
+            BASE="HEAD~1"
+          fi
+          FILES=$(git diff --name-only --diff-filter=ACMRT "$BASE" HEAD | grep '\.py$' || true)
+          echo "files=$FILES" >> "$GITHUB_OUTPUT"
+          echo "Changed Python files:"
+          echo "$FILES"
+
+      - name: Lint changed files with ruff
+        run: |
+          FILES="${{ steps.changed.outputs.files }}"
+          if [ -z "$FILES" ]; then
+            echo "No Python files changed. Skipping lint."
+            exit 0
+          fi
+          ruff check $FILES
+          ruff format --check $FILES
+
+      - name: Run console unit tests
+        run: |
+          python -m pytest console/tests/test_core.py console/tests/test_utils.py -v
+
+      # Playwright E2E tests require the full stack (PostgreSQL, Redis, etc.).
+      # Enable this job once a test environment is available in CI.
+      # - name: Run E2E tests
+      #   run: |
+      #     npm ci
+      #     npx playwright install --with-deps chromium
+      #     npx playwright test