feat: implement comprehensive i18n system with German and English support

- Created type-safe i18n system with TranslationKeys interface
- Added German (de) and English (en) translations with 160+ keys
- Implemented I18nContext provider and useI18n hook
- Added LanguageSwitcher component for language selection
- Refactored all major components to use translations:
  * Home page, StatsDashboard, DramOfTheDay
  * BottleGrid, EditBottleForm, CameraCapture
  * BuddyList, SessionList, TastingNoteForm
  * StatusSwitcher and bottle management features
- Implemented locale-aware currency formatting (EUR)
- Implemented locale-aware date formatting
- Added localStorage persistence for language preference
- Added automatic browser language detection
- Organized translations into 8 main categories
- System is extensible for additional languages

src/i18n/types.ts

@@ -0,0 +1,160 @@
+export type TranslationKeys = {
+    common: {
+        save: string;
+        cancel: string;
+        edit: string;
+        delete: string;
+        loading: string;
+        error: string;
+        success: string;
+        search: string;
+        back: string;
+        confirm: string;
+        check: string;
+        link: string;
+        none: string;
+    };
+    home: {
+        title: string;
+        logout: string;
+        stats: {
+            title: string;
+            totalValue: string;
+            activeBottles: string;
+            avgRating: string;
+            topDistillery: string;
+        };
+        dramOfDay: {
+            button: string;
+            rollAgain: string;
+            suggestion: string;
+            noOpenBottles: string;
+            title: string;
+            viewBottle: string;
+        };
+        searchPlaceholder: string;
+        noBottles: string;
+        collection: string;
+        reTry: string;
+        all: string;
+    };
+    grid: {
+        searchPlaceholder: string;
+        noResults: string;
+        sortBy: {
+            createdAt: string;
+            lastTasted: string;
+            name: string;
+        };
+        filter: {
+            category: string;
+            distillery: string;
+            status: string;
+        };
+        addSession: string;
+        addedOn: string;
+        reviewRequired: string;
+        unknownBottle: string;
+    };
+    bottle: {
+        details: string;
+        distillery: string;
+        category: string;
+        abv: string;
+        age: string;
+        years: string;
+        lastTasted: string;
+        neverTasted: string;
+        purchasePrice: string;
+        distilled: string;
+        bottled: string;
+        batch: string;
+        status: {
+            sealed: string;
+            open: string;
+            sampled: string;
+            empty: string;
+        };
+        whiskybaseId: string;
+        tastingNotes: string;
+        tastingNotesDesc: string;
+        noNotes: string;
+        editDetails: string;
+        editTitle: string;
+        autoSearch: string;
+        applyId: string;
+        saveChanges: string;
+        noMatchFound: string;
+        priceLabel: string;
+        nameLabel: string;
+        distilleryLabel: string;
+        categoryLabel: string;
+        abvLabel: string;
+        ageLabel: string;
+        distilledLabel: string;
+        bottledLabel: string;
+        batchLabel: string;
+        bottleStatus: string;
+    };
+    camera: {
+        scanBottle: string;
+        uploadImage: string;
+        analyzing: string;
+        analysisError: string;
+        matchFound: string;
+        notAWhisky: string;
+        lowConfidence: string;
+        saveToVault: string;
+        tastingNow: string;
+        backToList: string;
+        whiskybaseSearch: string;
+        searchingWb: string;
+        wbMatchFound: string;
+        magicShot: string;
+        saveSuccess: string;
+        later: string;
+        openingCamera: string;
+        saving: string;
+        nextBottle: string;
+        newPhoto: string;
+        inVault: string;
+        offlineNotice: string;
+        alreadyInVault: string;
+        alreadyInVaultDesc: string;
+        saveAnyway: string;
+        analysisSuccess: string;
+        results: string;
+        toVault: string;
+        authRequired: string;
+        processingError: string;
+    };
+    tasting: {
+        addNote: string;
+        isSample: string;
+        isBottle: string;
+        rating: string;
+        nose: string;
+        palate: string;
+        finish: string;
+        notesPlaceholder: string;
+        overall: string;
+        saveTasting: string;
+        participants: string;
+        addParticipant: string;
+    };
+    buddy: {
+        title: string;
+        addBuddy: string;
+        placeholder: string;
+        noBuddies: string;
+    };
+    session: {
+        title: string;
+        activeSession: string;
+        allSessions: string;
+        newSession: string;
+        sessionName: string;
+        noSessions: string;
+        expiryWarning: string;
+    };
+};