ci: enhance CI workflow to support pysqlite3 installation across multiple OS

* Added steps to install pysqlite3-binary for Linux, macOS, and Windows
* Created sitecustomize.py overrides to enable SQLite extensions in Python for each OS
* Updated PYTHONPATH environment variable accordingly

Author: atasoglu

.github/workflows/test.yml

@@ -85,6 +85,55 @@ jobs:
         pip install -e .
         pip install -r requirements-dev.txt
 
+    - name: Use pysqlite3 on Linux (enable SQLite extensions in Python)
+      if: runner.os == 'Linux'
+      run: |
+        pip install pysqlite3-binary
+        python - <<'PY'
+        import textwrap, pathlib
+        pathlib.Path('sitecustomize.py').write_text(textwrap.dedent('''
+        import pysqlite3 as sqlite3
+        import sys
+        sys.modules['sqlite3'] = sqlite3
+        sys.modules['sqlite3.dbapi2'] = sqlite3
+        ''').lstrip())
+        print('Wrote sitecustomize.py override for Linux')
+        PY
+        echo "PYTHONPATH=$PWD:$PYTHONPATH" >> $GITHUB_ENV
+
+    - name: Use pysqlite3 on macOS (enable SQLite extensions in Python)
+      if: runner.os == 'macOS'
+      run: |
+        pip install pysqlite3-binary
+        python - <<'PY'
+        import textwrap, pathlib
+        pathlib.Path('sitecustomize.py').write_text(textwrap.dedent('''
+        import pysqlite3 as sqlite3
+        import sys
+        sys.modules['sqlite3'] = sqlite3
+        sys.modules['sqlite3.dbapi2'] = sqlite3
+        ''').lstrip())
+        print('Wrote sitecustomize.py override for macOS')
+        PY
+        echo "PYTHONPATH=$PWD:$PYTHONPATH" >> $GITHUB_ENV
+
+    - name: Use pysqlite3 on Windows (enable SQLite extensions in Python)
+      if: runner.os == 'Windows'
+      shell: powershell
+      run: |
+        pip install pysqlite3-binary
+        python - <<'PY'
+        import textwrap, pathlib
+        pathlib.Path('sitecustomize.py').write_text(textwrap.dedent('''
+        import pysqlite3 as sqlite3
+        import sys
+        sys.modules['sqlite3'] = sqlite3
+        sys.modules['sqlite3.dbapi2'] = sqlite3
+        ''').lstrip())
+        print('Wrote sitecustomize.py override for Windows')
+        PY
+        "$env:PYTHONPATH=$pwd;${env:PYTHONPATH}" | Out-File -FilePath $env:GITHUB_ENV -Append -Encoding utf8
+
     - name: Lint with ruff
       run: ruff check .