Compose theme from the Daycompass design system #8

Bring the Daycompass design system into the app before the first real screen (#5).

• Color tokens for light and dark (same names), mapped onto a Material 3 ColorScheme plus a DcColors holder for the tokens Material has no slot for (edges, *-soft, focus, disabled-*, data colors).
• Typography: Fredoka (display, headings, numbers) and Nunito (UI text), both OFL. The variable TTFs from google/fonts are bundled; nothing is loaded from the network. The license texts ship in the APK.
• Spacing, radius and size tokens.
• Components needed by the pairing screen: DcButton (chunky bottom edge that collapses on press; primary, secondary, neutral; disabled and loading states) and DcTextField (visible label, helper and error text with an icon, 2dp control border).
• Material defaults that fight the brand are turned off: no ripple tint, no surface tint, elevation 0.
• Adaptive launcher icon: #23202E background with the compass as the foreground, plus a monochrome layer.

The design system README targets Flutter; this issue translates the same tokens and rules to Compose.