Share native theme components and fix dialog backdrop blur

Centralize native palettes, presets, typography, controls, menus, calendar rendering, and icon assets in ferese-theme. Reuse the shared components across the shell, settings, lock screen, authentication prompt, and screen-sharing chooser.

Attach themed dialogs to compositor-owned materials, correct backdrop capture and sampling across output transforms, smooth patterned backgrounds, and prevent clipped picker buttons with the configured shell font.

crates/ferese-theme/assets/icons/status/battery-25.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 32 24" role="img" aria-label="Battery 25">
+<rect x="2" y="6" width="25" height="12" rx="3" fill="none" stroke="currentColor" stroke-width="1.5"/>
+<rect x="28" y="10" width="2" height="4" rx="1" fill="currentColor"/>
+<rect x="5" y="9" width="4.75" height="6" rx="1.2" fill="#e0654f"/>
+</svg>