Port FixType filtering to current Fix common errors UI

[Blackspirits]

Purpose

Current-base audit/port of the top commit from upstream stack PR SubtitleEdit#14443, layered on draft #107.

This PR adds only the UI consumer of the FixType contract:

• an All/Time/Formatting/Dialog/Punctuation/Casing/Spacing/Characters/OCR filter;
• type filtering ANDed with the existing rule search;
• the previously-created search box is actually added to the step-1 toolbar;
• filtering always works from the profile's full rule list, preserving hidden rule selection;
• profile switches retain the active filter;
• type resolution comes from the fix classes, not a duplicated UI mapping;
• language strings and focused UI tests are included.

Rebase integrity

The original top commit was based on a September 2 tree. Two later upstream improvements were present in current main but absent from the author's old branch:

• AnalysingMinimumVisibleMilliseconds / AnalysingPaintDelayMilliseconds are test-adjustable internal static values;
• two action labels use UiUtil.ScaledFontSize(12).

Both current behaviors are explicitly preserved in this port. After those reconciliations, per-file diff counts match the original top commit exactly.

Validation

• base: draft Port FixType contract to current Fix common errors rules #107, final HEAD cd4ad6454a55651d6b2563fed0babc58b8be9991
• this branch was rebuilt cleanly as exactly one top commit on that final base
• final HEAD: b56908f79f8e7d745d1cd77c865af30ca7fd1840
• focused tests from Add a FixType filter to the Fix common errors rule list SubtitleEdit/subtitleedit#14443 retained, plus an explicit FixDoubleGreaterThan -> Dialog taxonomy assertion
• full solution restore passed
• full solution build passed
• full solution test suite passed on the first run
• UI suite: 5,168 passed, 9 skipped, 0 failed (5,177 total)
• retry step was not used
• validation run: #34788005507
• audit draft only; no merge/promotion intended

AI assistance: ChatGPT was used to port the stale stacked PR while preserving newer upstream testability and scaled-font behavior.

[Blackspirits]

Final independent re-check: this branch is now exactly one top commit on the final #107 HEAD. The stale author's branch would have reverted the current analyzing timing test hooks and two UiUtil.ScaledFontSize calls; both newer behaviors are preserved. Save/apply use AllFixRules, while Select all/Invert intentionally act only on visible filtered rows. The focused suite also pins FixDoubleGreaterThan to Dialog. Full CI #34788005507 passed restore, build and the complete solution suite on the first run; UITests reported 5,168 passed, 9 skipped and 0 failed. Retry was not used. No blocker identified. Keep draft; no merge performed.