Make xhtml2pdf optional, fix install on Linux without libcairo (#2659)

* Make xhtml2pdf optional, fix install on Linux without libcairo

Move xhtml2pdf to the new [pdf] extra so default `pip install maigret`
no longer pulls pycairo (which has no Linux/macOS wheels and breaks the
build without libcairo2-dev). save_pdf_report now raises a clear
RuntimeError pointing to `pip install 'maigret[pdf]'`, and the CLI
turns it into a friendly warning instead of a crash. Adds tests
covering the missing-extra path, plus per-OS install docs.

Fix for #2657, #2534

* Make arabic-reshaper and python-bidi optional; idempotent update of db_meta.json and sites.md

* Regenerated poerty.lock

* Update CI workflow to cover minimal installation without PDF deps

.github/workflows/python-package.yml

@@ -46,4 +46,33 @@ jobs:
         uses: actions/upload-artifact@v4
         with:
           name: htmlcov-${{ strategy.job-index }}
-          path: htmlcov
+          path: htmlcov
+
+  minimal-install:
+    # Verify a fresh `pip install maigret` succeeds and the test suite
+    # passes WITHOUT the optional [pdf] extra and WITHOUT system cairo.
+    # Catches regressions where core code accidentally grows a hard
+    # dependency on xhtml2pdf / pycairo / libcairo2.
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.12"
+
+      - name: Install Maigret without [pdf] extra (no libcairo on host)
+        run: |
+          python -m pip install --upgrade pip
+          pip install .
+          pip install pytest pytest-asyncio pytest-rerunfailures pytest-httpserver
+
+      - name: Smoke-check the install
+        run: |
+          python -c "import maigret; from maigret.report import save_pdf_report; print('import OK')"
+          maigret --version
+
+      - name: Run tests without [pdf] extra
+        run: pytest --reruns 3 --reruns-delay 5 tests