feat: L'Ami Fiduciaire V1.0.0 — full codebase with Story 0.1 complete

Initial commit of the L'Ami Fiduciaire SaaS platform built on Laravel 12,
Vue 3, Inertia.js 2, and Tailwind CSS 4.

Story 0.1 (rename folders to declarations in database) is implemented and
code-reviewed: migration, rollback, and 6 Pest tests all passing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

resources/js/composables/useAppearance.ts

@@ -0,0 +1,124 @@
+import type { ComputedRef, Ref } from 'vue';
+import { computed, onMounted, ref } from 'vue';
+import type { Appearance, ResolvedAppearance } from '@/types';
+
+export type { Appearance, ResolvedAppearance };
+
+export type UseAppearanceReturn = {
+    appearance: Ref<Appearance>;
+    resolvedAppearance: ComputedRef<ResolvedAppearance>;
+    updateAppearance: (value: Appearance) => void;
+};
+
+export function updateTheme(value: Appearance): void {
+    if (typeof window === 'undefined') {
+        return;
+    }
+
+    if (value === 'system') {
+        const mediaQueryList = window.matchMedia(
+            '(prefers-color-scheme: dark)',
+        );
+        const systemTheme = mediaQueryList.matches ? 'dark' : 'light';
+
+        document.documentElement.classList.toggle(
+            'dark',
+            systemTheme === 'dark',
+        );
+    } else {
+        document.documentElement.classList.toggle('dark', value === 'dark');
+    }
+}
+
+const setCookie = (name: string, value: string, days = 365) => {
+    if (typeof document === 'undefined') {
+        return;
+    }
+
+    const maxAge = days * 24 * 60 * 60;
+
+    document.cookie = `${name}=${value};path=/;max-age=${maxAge};SameSite=Lax`;
+};
+
+const mediaQuery = () => {
+    if (typeof window === 'undefined') {
+        return null;
+    }
+
+    return window.matchMedia('(prefers-color-scheme: dark)');
+};
+
+const getStoredAppearance = () => {
+    if (typeof window === 'undefined') {
+        return null;
+    }
+
+    return localStorage.getItem('appearance') as Appearance | null;
+};
+
+const prefersDark = (): boolean => {
+    if (typeof window === 'undefined') {
+        return false;
+    }
+
+    return window.matchMedia('(prefers-color-scheme: dark)').matches;
+};
+
+const handleSystemThemeChange = () => {
+    const currentAppearance = getStoredAppearance();
+
+    updateTheme(currentAppearance || 'system');
+};
+
+export function initializeTheme(): void {
+    if (typeof window === 'undefined') {
+        return;
+    }
+
+    // Initialize theme from saved preference or default to system...
+    const savedAppearance = getStoredAppearance();
+    updateTheme(savedAppearance || 'system');
+
+    // Set up system theme change listener...
+    mediaQuery()?.addEventListener('change', handleSystemThemeChange);
+}
+
+const appearance = ref<Appearance>('system');
+
+export function useAppearance(): UseAppearanceReturn {
+    onMounted(() => {
+        const savedAppearance = localStorage.getItem(
+            'appearance',
+        ) as Appearance | null;
+
+        if (savedAppearance) {
+            appearance.value = savedAppearance;
+        }
+    });
+
+    const resolvedAppearance = computed<ResolvedAppearance>(() => {
+        if (appearance.value === 'system') {
+            return prefersDark() ? 'dark' : 'light';
+        }
+
+        return appearance.value;
+    });
+
+    function updateAppearance(value: Appearance) {
+        appearance.value = value;
+
+        // Store in localStorage for client-side persistence...
+        localStorage.setItem('appearance', value);
+
+        // Store in cookie for SSR...
+        setCookie('appearance', value);
+
+        updateTheme(value);
+    }
+
+    return {
+        appearance,
+        resolvedAppearance,
+        updateAppearance,
+    };
+}