feat(meals): customizable meal type visibility in Settings (#14)

Users can now toggle which meal types (breakfast, lunch, dinner, snack)
are displayed in the meal planner via a new Settings section. Preference
is stored household-wide in sync_config and applied as a filter on the
meals page. Includes preferences API, i18n (DE/EN/IT), and Settings UI.

server/index.js

@@ -23,6 +23,7 @@ import notesRouter from './routes/notes.js';
 import contactsRouter from './routes/contacts.js';
 import budgetRouter from './routes/budget.js';
 import weatherRouter from './routes/weather.js';
+import preferencesRouter from './routes/preferences.js';
 
 const log     = createLogger('Server');
 const logSync = createLogger('Sync');
@@ -160,6 +161,7 @@ app.use('/api/v1/notes', notesRouter);
 app.use('/api/v1/contacts', contactsRouter);
 app.use('/api/v1/budget', budgetRouter);
 app.use('/api/v1/weather', weatherRouter);
+app.use('/api/v1/preferences', preferencesRouter);
 
 // --------------------------------------------------------
 // Health-Check (für Docker)