feat: Setup projet Classeo avec infrastructure Docker et architecture DDD

Configure l'environnement de développement complet avec Docker Compose,
structure DDD 4 Bounded Contexts, et pipeline CI/CD GitHub Actions.

Corrections compatibilité CI:
- Symfony 8 nécessite monolog-bundle ^4.0 (la v3.x ne supporte que jusqu'à Symfony 7)
- ESLint v9 nécessite flat config (eslint.config.js) - le format .eslintrc.cjs est obsolète

frontend/tailwind.config.js

@@ -0,0 +1,53 @@
+/** @type {import('tailwindcss').Config} */
+export default {
+	darkMode: 'class',
+	content: ['./src/**/*.{html,js,svelte,ts}'],
+	theme: {
+		extend: {
+			colors: {
+				border: 'hsl(var(--border))',
+				input: 'hsl(var(--input))',
+				ring: 'hsl(var(--ring))',
+				background: 'hsl(var(--background))',
+				foreground: 'hsl(var(--foreground))',
+				primary: {
+					DEFAULT: 'hsl(var(--primary))',
+					foreground: 'hsl(var(--primary-foreground))'
+				},
+				secondary: {
+					DEFAULT: 'hsl(var(--secondary))',
+					foreground: 'hsl(var(--secondary-foreground))'
+				},
+				destructive: {
+					DEFAULT: 'hsl(var(--destructive))',
+					foreground: 'hsl(var(--destructive-foreground))'
+				},
+				muted: {
+					DEFAULT: 'hsl(var(--muted))',
+					foreground: 'hsl(var(--muted-foreground))'
+				},
+				accent: {
+					DEFAULT: 'hsl(var(--accent))',
+					foreground: 'hsl(var(--accent-foreground))'
+				},
+				popover: {
+					DEFAULT: 'hsl(var(--popover))',
+					foreground: 'hsl(var(--popover-foreground))'
+				},
+				card: {
+					DEFAULT: 'hsl(var(--card))',
+					foreground: 'hsl(var(--card-foreground))'
+				}
+			},
+			borderRadius: {
+				lg: 'var(--radius)',
+				md: 'calc(var(--radius) - 2px)',
+				sm: 'calc(var(--radius) - 4px)'
+			},
+			fontFamily: {
+				sans: ['Inter', 'system-ui', 'sans-serif']
+			}
+		}
+	},
+	plugins: [require('@tailwindcss/forms'), require('@tailwindcss/typography')]
+};