NCE-15 NCE-18 NCE-23 NCE-26: integrate remaining v3.1.0 QA fixes

[FortPT]

Summary

Integrate the remaining v3.1.0 QA fixes onto release/v3.1.0-amber-webui without reverting the Amber WebUI.

NCE-15

• Expand Regional Settings language choices.
• Use clean native-language labels without country names in the visible dropdown.
• Keep legacy en-US / pt-BR values valid for existing saved settings.
• Associate each locale with a sensible default IANA timezone.
• Replace the free-form timezone field with a selectable timezone dropdown that users can still override.
• Add packaged UI translation catalogs for all newly offered non-English languages.
• Treat Language / Timezone / Time format as draft values until Save settings succeeds.
• Discard unsaved Regional Settings when navigating away and restore persisted values when returning.
• Apply the selected language to the WebUI only after the preferences save succeeds.
• Expand backend and legacy WebUI language validation to the same locale set.

NCE-18

• Make the main WebUI own Save picture visibility/disabled state.
• Hide/disable the button during save and after successful save.
• Restore it on failed save when an image remains selected.
• Remove the conflicting QA helper that could re-show stale save state.

NCE-23

• Preserve Audit Log entries-per-page selection across refresh/navigation.
• Support the selected page size in the audit pagination API.

NCE-26

• Reset avatar editor state when removing a profile picture.
• Clear the file selection, hide the editor, reset zoom, release the decoded image, and hide/disable Save picture.

Validation on VM-09

• node --check src/webui/i18n.js: passed
• node --check src/webui/app.js: passed
• node --check src/webui/qa_patch.js: passed
• python -m compileall -q src: passed in earlier combined-branch validation
• pytest -q tests/test_webui.py: 11 passed
• broader test run excluding tests/test_brand_identity.py: 1032 passed
• git diff --check: clean

tests/test_brand_identity.py is omitted only on the non-elevated VM checkout because it recursively reads /docker/nowlert-ce/config/config.yaml, which is not readable by the normal VM user. CI should run it in a clean checkout.

Development gate

Keep this PR in draft until the updated branch image has been deployed to CE Development and NCE-15 / NCE-18 / NCE-23 / NCE-26 have been checked in the running v3.1.0 UI. NCE-18 Save picture already passed Development validation; NCE-15 requires a fresh Development retest for translation and save/discard semantics.

Release path

This PR targets release/v3.1.0-amber-webui. Once validated and merged, PR #176 (release/v3.1.0-amber-webui -> main) will carry these fixes into the v3.1.0 release candidate.

Refs: NCE-15, NCE-18, NCE-23, NCE-26

[FortPT]

Development UI validation update:

• NCE-18 Save picture behavior passed.
• NCE-15 still has two defects and this PR should remain draft:
  1. Newly added non-Portuguese locales do not translate the WebUI because the current client-side localization dictionary only covers Portuguese; other locales fall back to English.
  2. Unsaved Regional Settings form selections remain visible after navigating away and back, even though they were never persisted. The form needs explicit draft-vs-saved semantics so only a successful Save settings applies/persists the values.

Expected next patch: leaving Settings without saving restores persisted values; successful save updates state.preferences and then applies language/timezone/time format; supported locale choices receive actual UI translations rather than silent English fallback.

Jira NCE-15 has been updated with the same Development findings.