Polish focus, fonts, and tooltip alignment

[Widthdom]

Summary

• Give the Create button the same rounded two-pixel focus border used by the Command and Search fields.
• Bundle Inter Regular, SemiBold, and Bold under the SIL Open Font License and apply the embedded family only on Windows.
• Keep the macOS/Linux platform font stacks unchanged; Windows falls back from Inter to Yu Gothic UI or Meiryo for unsupported characters.
• Vertically center compact Create and window-caption tooltips with a shared optical-alignment style.
• Add a focused source guard plus bilingual README and changelog updates.

Root cause

The Create button used a zero-width border and did not suppress the default focus adorner, so its focused appearance diverged from the top-bar text fields. Windows also overrode the intended Inter stack with an installed Segoe family even though Inter was not bundled. Finally, the caption tooltip style had more bottom margin than top margin, which shifted its text above the visual center.

The first font implementation applied the embedded Inter family to every platform. Because Inter does not contain Japanese glyphs, this caused missing-glyph boxes on macOS. The follow-up scopes the embedded family to the existing .windows class and uses Avalonia's composite font family support for Windows Japanese fallbacks.

User impact

Keyboard focus is visually consistent across the top bar, Windows typography no longer depends on the installed Latin UI font, Japanese text remains supported on Windows, macOS/Linux retain their prior typography, and compact button tooltips read as vertically centered.

Validation

• dotnet build Praxis.Avalonia/Praxis.Avalonia.csproj -c Release --nologo
• dotnet test Praxis.Tests/Praxis.Tests.csproj -c Release --nologo — 614 passed
• dotnet build Praxis.slnx -c Debug --nologo
• Release app startup smoke test on macOS — no XAML or embedded-font resolution errors
• git diff --check
• cdidx status --check --json — fresh, no failed readiness checks

Screenshots

The reported macOS missing-glyph screenshot was used to identify the regression. A corrected capture could not be created in the automation session because macOS Screen Recording permission was unavailable. A Windows capture is still recommended to verify ClearType rendering and final optical alignment on the target platform.