The flutter_test default font draws every glyph as a box, so the wordmark was
unreadable. Load the OFL Titan One TTF via FontLoader in the generator and
render 'Block Seasons' + tagline with it; fit the text within the 1024 width.
Font used only by the asset generator, not bundled in the app.
Introduces AppIconMark (navy gradient field + 2×2 glossy blocks reusing
paintGlossyTile) and a testWidgets generator that writes icon.png,
icon_background.png, and icon_foreground.png to assets/icon/ for the
upcoming flutter_launcher_icons task.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>