🌐 feat: add i18n support to 6 web apps

Add internationalization (DE + EN) to previously missing apps:
- todo: task management translations
- skilltree: skill/XP system translations
- nutriphi: nutrition tracking translations
- planta: plant care translations
- questions: research app translations
- matrix: chat client translations (layout integration)

Each app includes:
- svelte-i18n setup with SSR support
- localStorage persistence ({app}_locale pattern)
- i18n loading state in +layout.svelte
- German (default) and English translations

Updated CONSISTENCY_REPORT.md to mark i18n task as complete.

Also includes:
- mana-tts service placeholder files

apps/nutriphi/apps/web/src/lib/i18n/index.ts

@@ -0,0 +1,49 @@
+import { browser } from '$app/environment';
+import { init, register, locale, waitLocale } from 'svelte-i18n';
+
+// List of supported locales
+export const supportedLocales = ['de', 'en'] as const;
+export type SupportedLocale = (typeof supportedLocales)[number];
+
+// Default locale
+const defaultLocale = 'de';
+
+// Register all available locales
+register('de', () => import('./locales/de.json'));
+register('en', () => import('./locales/en.json'));
+
+// Get initial locale from browser or localStorage
+function getInitialLocale(): SupportedLocale {
+	if (browser) {
+		// Check localStorage first
+		const stored = localStorage.getItem('nutriphi_locale');
+		if (stored && supportedLocales.includes(stored as SupportedLocale)) {
+			return stored as SupportedLocale;
+		}
+
+		// Fall back to browser language
+		const browserLang = navigator.language.split('-')[0];
+		if (supportedLocales.includes(browserLang as SupportedLocale)) {
+			return browserLang as SupportedLocale;
+		}
+	}
+
+	return defaultLocale;
+}
+
+// Initialize i18n at module scope (required for SSR)
+init({
+	fallbackLocale: defaultLocale,
+	initialLocale: getInitialLocale(),
+});
+
+// Set locale and persist to localStorage
+export function setLocale(newLocale: SupportedLocale) {
+	locale.set(newLocale);
+	if (browser) {
+		localStorage.setItem('nutriphi_locale', newLocale);
+	}
+}
+
+// Wait for locale to be loaded (useful for SSR)
+export { waitLocale };

apps/nutriphi/apps/web/src/lib/i18n/locales/de.json

@@ -0,0 +1,89 @@
+{
+	"app": {
+		"name": "NutriPhi",
+		"loading": "Laden...",
+		"tagline": "Ernährung verstehen"
+	},
+	"nav": {
+		"dashboard": "Dashboard",
+		"meals": "Mahlzeiten",
+		"goals": "Ziele",
+		"favorites": "Favoriten",
+		"stats": "Statistiken",
+		"settings": "Einstellungen"
+	},
+	"meal": {
+		"add": "Mahlzeit hinzufügen",
+		"edit": "Mahlzeit bearbeiten",
+		"delete": "Mahlzeit löschen",
+		"photo": "Foto aufnehmen",
+		"text": "Beschreiben",
+		"analyzing": "Analysiere...",
+		"noMeals": "Noch keine Mahlzeiten",
+		"breakfast": "Frühstück",
+		"lunch": "Mittagessen",
+		"dinner": "Abendessen",
+		"snack": "Snack"
+	},
+	"nutrition": {
+		"calories": "Kalorien",
+		"protein": "Protein",
+		"carbs": "Kohlenhydrate",
+		"fat": "Fett",
+		"fiber": "Ballaststoffe",
+		"sugar": "Zucker",
+		"kcal": "kcal",
+		"grams": "g"
+	},
+	"goals": {
+		"daily": "Tagesziele",
+		"setGoals": "Ziele setzen",
+		"calories": "Kalorien-Ziel",
+		"protein": "Protein-Ziel",
+		"carbs": "Kohlenhydrate-Ziel",
+		"fat": "Fett-Ziel",
+		"progress": "Fortschritt"
+	},
+	"stats": {
+		"today": "Heute",
+		"week": "Diese Woche",
+		"remaining": "Verbleibend",
+		"consumed": "Verzehrt",
+		"average": "Durchschnitt"
+	},
+	"favorites": {
+		"add": "Zu Favoriten",
+		"remove": "Aus Favoriten entfernen",
+		"noFavorites": "Keine Favoriten",
+		"useAgain": "Erneut verwenden"
+	},
+	"auth": {
+		"login": "Anmelden",
+		"logout": "Abmelden",
+		"register": "Registrieren"
+	},
+	"common": {
+		"save": "Speichern",
+		"cancel": "Abbrechen",
+		"delete": "Löschen",
+		"edit": "Bearbeiten",
+		"add": "Hinzufügen",
+		"close": "Schließen",
+		"search": "Suchen",
+		"error": "Fehler",
+		"success": "Erfolgreich",
+		"loading": "Laden..."
+	},
+	"errors": {
+		"loadMeals": "Mahlzeiten konnten nicht geladen werden",
+		"analyzeFailed": "Analyse fehlgeschlagen",
+		"saveFailed": "Speichern fehlgeschlagen",
+		"loadGoals": "Ziele konnten nicht geladen werden"
+	},
+	"success": {
+		"mealAdded": "Mahlzeit hinzugefügt",
+		"mealDeleted": "Mahlzeit gelöscht",
+		"goalsSaved": "Ziele gespeichert",
+		"favoriteAdded": "Zu Favoriten hinzugefügt"
+	}
+}

apps/nutriphi/apps/web/src/lib/i18n/locales/en.json

@@ -0,0 +1,89 @@
+{
+	"app": {
+		"name": "NutriPhi",
+		"loading": "Loading...",
+		"tagline": "Understand nutrition"
+	},
+	"nav": {
+		"dashboard": "Dashboard",
+		"meals": "Meals",
+		"goals": "Goals",
+		"favorites": "Favorites",
+		"stats": "Statistics",
+		"settings": "Settings"
+	},
+	"meal": {
+		"add": "Add meal",
+		"edit": "Edit meal",
+		"delete": "Delete meal",
+		"photo": "Take photo",
+		"text": "Describe",
+		"analyzing": "Analyzing...",
+		"noMeals": "No meals yet",
+		"breakfast": "Breakfast",
+		"lunch": "Lunch",
+		"dinner": "Dinner",
+		"snack": "Snack"
+	},
+	"nutrition": {
+		"calories": "Calories",
+		"protein": "Protein",
+		"carbs": "Carbohydrates",
+		"fat": "Fat",
+		"fiber": "Fiber",
+		"sugar": "Sugar",
+		"kcal": "kcal",
+		"grams": "g"
+	},
+	"goals": {
+		"daily": "Daily goals",
+		"setGoals": "Set goals",
+		"calories": "Calorie goal",
+		"protein": "Protein goal",
+		"carbs": "Carbohydrate goal",
+		"fat": "Fat goal",
+		"progress": "Progress"
+	},
+	"stats": {
+		"today": "Today",
+		"week": "This week",
+		"remaining": "Remaining",
+		"consumed": "Consumed",
+		"average": "Average"
+	},
+	"favorites": {
+		"add": "Add to favorites",
+		"remove": "Remove from favorites",
+		"noFavorites": "No favorites",
+		"useAgain": "Use again"
+	},
+	"auth": {
+		"login": "Login",
+		"logout": "Logout",
+		"register": "Register"
+	},
+	"common": {
+		"save": "Save",
+		"cancel": "Cancel",
+		"delete": "Delete",
+		"edit": "Edit",
+		"add": "Add",
+		"close": "Close",
+		"search": "Search",
+		"error": "Error",
+		"success": "Success",
+		"loading": "Loading..."
+	},
+	"errors": {
+		"loadMeals": "Failed to load meals",
+		"analyzeFailed": "Analysis failed",
+		"saveFailed": "Failed to save",
+		"loadGoals": "Failed to load goals"
+	},
+	"success": {
+		"mealAdded": "Meal added",
+		"mealDeleted": "Meal deleted",
+		"goalsSaved": "Goals saved",
+		"favoriteAdded": "Added to favorites"
+	}
+}

apps/nutriphi/apps/web/src/routes/+layout.svelte

@@ -1,5 +1,7 @@
 <script lang="ts">
 	import '../app.css';
+	import '$lib/i18n';
+	import { isLoading as i18nLoading, _ as t } from 'svelte-i18n';
 	import { authStore } from '$lib/stores/auth.svelte';
 
 	let { children } = $props();
@@ -11,7 +13,13 @@
 </script>
 
 <svelte:head>
-	<title>NutriPhi - Ernährung verstehen</title>
+	<title>{$t('app.name')} - {$t('app.tagline')}</title>
 </svelte:head>
 
-{@render children()}
+{#if $i18nLoading}
+	<div class="flex min-h-screen items-center justify-center">
+		<p>{$t('app.loading')}</p>
+	</div>
+{:else}
+	{@render children()}
+{/if}