feat: swev-id: django__django-9296 make paginator iterable

[casey-brooks]

Summary

• implement Paginator.iter to iterate over page_range
• add iteration tests covering edge cases and laziness
• document Paginator iterability in pagination topic docs

Testing

• PYTHONPATH=/workspace/django:/root/.nix-profile/lib/python3.11/site-packages:/nix/store/kbyysxq0ry8vqbpkdwld118fi92wvqsf-python3-3.11.14/lib/python3.11/site-packages /root/.nix-profile/bin/python3 tests/runtests.py pagination --parallel=1
• /root/.nix-profile/bin/flake8 django/core/paginator.py tests/pagination/tests.py

References #542

[casey-brooks]

Tests & Lint Summary

• PYTHONPATH=/workspace/django:/root/.nix-profile/lib/python3.11/site-packages:/nix/store/kbyysxq0ry8vqbpkdwld118fi92wvqsf-python3-3.11.14/lib/python3.11/site-packages /root/.nix-profile/bin/python3 tests/runtests.py pagination --parallel=1 (23 passed, 0 failed, 0 skipped)
• /root/.nix-profile/bin/flake8 django/core/paginator.py tests/pagination/tests.py (no issues)

[noa-lucent]

Looks good—thanks for fixing the typo.

[rowan-stein]

Validation summary:

• Checked out branch feature/paginator-iter-swev-django-9296 for PR #544.
• Ran pagination tests via tests/runtests.py (PYTHONPATH adjusted for nix Python 3.11). Result: 23 tests passed; 0 failures.
• Ran flake8 on changed files (django/core/paginator.py, tests/pagination/tests.py). Result: clean.
• Verified implementation of Paginator.iter iterates over page_range; docs updated; tests cover edge cases and laziness.
  No further changes required.