Respect pydocstyle add-select and add-ignore settings

[alloutflo]

Fixes #626

Summary

• apply addSelect and addIgnore independently of the selected basic error list
• add regression coverage for combining addIgnore with select and addSelect with ignore
• clarify the generated configuration reference for both additive settings

Tests

• pytest -q test/plugins/test_pydocstyle_lint.py (6 passed)
• pytest -o addopts="" -q test/ -k "not test_missing_message" (203 passed, 9 skipped, 1 deselected)
• ruff check pylsp test
• ruff format --check pylsp test
• JSON schema validation and generated configuration sync check

Local baseline note

test_missing_message has an unrelated teardown error on the unchanged develop branch with local Python 3.14 (config is None during shutdown), so it was excluded from the second full-suite run after confirming the same behavior against the baseline.

[alloutflo]

Maintainer handoff: the current head 7f89601a is mergeable and up to date with develop (0 commits behind). All four PR workflow runs—Linux, Windows, macOS, and static analysis—ended as action_required before creating any jobs (0 jobs each), so there is no contributor-side CI failure or log to fix.

The focused tests, broader test run, Ruff checks, and generated-configuration validation are recorded in the PR description. Please approve the fork workflows when convenient; if an actual job then fails, I can address that concrete failure.