feat: Reinitialize frontend with SvelteKit and TypeScript

- Delete old Vite+Svelte frontend
- Initialize new SvelteKit project with TypeScript
- Configure Tailwind CSS v4 + DaisyUI
- Implement JWT authentication with auto-refresh
- Create login page with form validation (Zod)
- Add protected route guards
- Update Docker configuration for single-stage build
- Add E2E tests with Playwright (6/11 passing)
- Fix Svelte 5 reactivity with $state() runes

Known issues:
- 5 E2E tests failing (timing/async issues)
- Token refresh implementation needs debugging
- Validation error display timing

frontend/.prettierrc

@@ -0,0 +1,8 @@
+{
+  "useTabs": false,
+  "singleQuote": true,
+  "trailingComma": "es5",
+  "printWidth": 100,
+  "plugins": ["prettier-plugin-svelte", "prettier-plugin-tailwindcss"],
+  "overrides": [{ "files": "*.svelte", "options": { "parser": "svelte" } }]
+}