Linux perf: ReadyToRun publish, faster MIME/icon lookup

[MemerGamer]

Builds on #53. Based on linux/main (includes #55 crash fix and #52 incremental listing).

Measured (Release self-contained publish, headless Xvfb, software GL, nice 19)

	before	after
Cold start: window appears	1.7-2.0 s	1.2 s
Cold start: Home content / settled	3.5-3.9 s / 4.3-5.1 s	2.6 s / 3.3-3.5 s
Methods JIT-compiled in a 45 s session	46,342	17,516
Switch to Grid, 1000 files (first content)	5.3 s blank	< 0.5 s
Switch to Grid, 10,000 files (UI-thread busy)	10.6 s	1.0 s
Scroll/PageDown/End in Grid, 10,000 files (UI-thread busy, ~15 s window)	10.9 s	1.5 s
Working set after Grid + scroll, 10,000 files	1.17-2.0 GB (grows with scrolling)	~0.78 GB, flat
GC pause total in a grid session	2.8 s	1.2 s
Watcher add/remove of 3 files in a 1000-file list: blank list	350-450 ms	0 ms

Changes

• ReadyToRun for Linux Release publishes (it was silently not applied).
• Grid/Cards virtualization on Uno (src/Files.App.UnoVirtualization): ItemsWrapGrid is a stub on Skia, so the layouts used a non-virtualizing WrapPanel that realized every item. New VirtualizingWrapGrid plugs a wrapping layout into Uno's VirtualizingPanelLayout. Uno.UI is publicized with Krafs.Publicizer in a separate project, because publicizing it in Files.App breaks the Uno XAML generator. Windows still uses ItemsWrapGrid (#if !WINDOWS). Selection, keyboard nav (including the Linux: integration sweep fixes (preview pane, omnibar, list keys, details) #53 Home/End/PageUp/PageDown handler), context menu and thumbnails-on-realize work as in Details (checked headless: arrows, PageDown/Up, End -> last item, right-click menu).
• Svg.Skia typeface lookups are memoized: every SVG paint went through SKFontManager.GetFontStyles, whose style sets were disposed on the finalizer thread (about 16 s of finalizer samples in a session on a box with 12k fonts; now none).
• MIME glob index, MIME XML and icon-name caches. Review fix: cached MIME XML and misses are re-checked (mtime / re-probe) every 5 s, so a newly installed MIME type appears without a restart (RecheckInterval, with a test).
• Watcher changes now update the displayed list with individual Remove/Insert (when <= 64 changes, same order, no grouping) instead of Clear + Reset, which blanked the whole list.

Not done / next

• Resize black area: Uno's X11 host already renders on the first ConfigureNotify; the delay is full relayout plus GL surface recreation. Setting the X window background to the theme colour needs a native handle and can't be verified without a compositor (KWin/XWayland), so it is left out.
• Remaining blank on F5 / navigation (150-300 ms) is a full reload by design.
• Grouped Grid view is not virtualized specially; unchanged from before apart from the new panel (group headers untested).

Tests: Files.Platform.Tests 758 passed, 7 skipped.

🤖 Generated with Claude Code

https://claude.ai/code/session_01LeKXJc3DnK3PzAqwgA72NY