Expand DevTools adding test windows

[DavidGBrett]

Summary by cubic

Expanded DevTools in About settings by replacing the flyout with a structured expander and adding test windows for Report, Progress, Plugin Update, and Message. This makes tools easier to find and test.

Summary of changes

• Changed: Replaced the single DevTools button + flyout with a SettingsExpander listing each action as its own SettingsCard.
• Added: Commands and UI to open test Report, Progress (async with cancel), Plugin Update, and Message windows; new localization strings for these actions and a generic "Open Folder" label.
• Removed: The DevTools flyout menu and its grouped actions.
• Memory impact: Minimal. Test windows are created on demand and disposed on close; the progress demo runs for up to 1 minute with small, temporary allocations.
• Security risks: None. Actions are local-only (open folders, show windows); no new I/O, network, or privilege changes.
• Unit tests: None added (UI-only changes).

Release Note
DevTools in About now shows clear buttons for each action and includes test windows for report, progress, plugin updates, and messages.

^{Written for commit f7dfda4. Summary will update on new commits.}