chore: add project scaffolding and resources

This initial commit scaffolds the project with essential docs, assets, and build configs.
It adds Android icons, design assets, and release metadata to support mobile targets.
A fastlane config and F-Droid manifest are included to streamline builds.

- Adds F-Droid configuration for automated builds
- Includes license and privacy policy documents
- Provides app icons and assets for Android and design system

design/icon-proposals/01-frame-flow.svg

@@ -0,0 +1,11 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512">
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+  <g transform="rotate(-8 236 258)">
+    <rect x="112" y="111" width="250" height="316" rx="48" fill="#8fbd91"/>
+  </g>
+  <rect x="142" y="78" width="258" height="330" rx="49" fill="#f8faf4"/>
+  <circle cx="326" cy="153" r="30" fill="#f2c85b"/>
+  <path d="M163 330 238 226l54 69 38-44 51 65v54c0 11-9 20-20 20H181c-11 0-20-9-20-20Z" fill="#0f5b32"/>
+  <path d="M342 74c39 12 69 42 82 80" fill="none" stroke="#dcebd8" stroke-width="18" stroke-linecap="round"/>
+  <path d="m408 128 18 30 11-33Z" fill="#dcebd8"/>
+</svg>