feat: migrate frontend React 18 → Svelte 5 + SvelteKit

Core logic portable (economy, balance, cosmetics, migrateSave) — zero rewrite.
136 tests green, identiques. Backend inchangé.

- Svelte 5 runes stores (game, auth, toast) remplacent Zustand
- SvelteKit adapter-static SPA (dist/ output, fallback index.html)
- Tailwind v4 conservé, design system .gp-* porté
- Transitions natives : slide, fly, scale, fade sur toute l'UI
- Sidebar tabbée (Production/Evolution/Collection) + CollapsiblePanel
- Mobile bottom sheet avec FAB toggle + backdrop blur
- Click particles réactifs Svelte (plus de DOM impératif)
- TadpoleSprite bounce + glow ring au clic
- Guide refait en accordéon, Achievements avec filtres
- a11y : focus-visible, Escape modals, aria-current, aria-labels
- CI/CD adapté (tests + build + rsync)
- Build 504K (vs ~1.2MB React)

Frontend/README.md

@@ -1,11 +1,42 @@
-# Clickerz — Tetard Universe
+# sv
 
-Idle clicker game. Fais éclore des têtards, construis ton empire et domine le marais.
+Everything you need to build a Svelte project, powered by [`sv`](https://github.com/sveltejs/cli).
 
-### Stack
+## Creating a project
 
-React · Vite · SCSS · Tailwind · Zustand
+If you're seeing this, you've probably already done this step. Congrats!
 
-### Credits
+```sh
+# create a new project
+npx sv create my-app
+```
 
-Développé par [Kevin T](https://github.com/tetardtek) · Powered by Brain
+To recreate this project with the same configuration:
+
+```sh
+# recreate this project
+npx sv@0.13.0 create --template minimal --types ts --no-install Frontend-svelte
+```
+
+## Developing
+
+Once you've created a project and installed dependencies with `npm install` (or `pnpm install` or `yarn`), start a development server:
+
+```sh
+npm run dev
+
+# or start the server and open the app in a new browser tab
+npm run dev -- --open
+```
+
+## Building
+
+To create a production version of your app:
+
+```sh
+npm run build
+```
+
+You can preview the production build with `npm run preview`.
+
+> To deploy your app, you may need to install an [adapter](https://svelte.dev/docs/kit/adapters) for your target environment.