Fix skeleton entry deletion and add hide suggestions toggle (#619)

- Revert filled skeleton entries back to skeleton on delete instead of permanently removing them
- Add per-user hide_skeletons preference on journey_contributors (migration 99)
- Add PATCH /journeys/:id/preferences endpoint for toggling skeleton visibility
- Add Eye/EyeOff toggle button with custom tooltip in journey detail header
- Filter skeleton entries from timeline when hidden
- Add i18n keys for all 14 languages

server/src/db/migrations.ts

@@ -1574,6 +1574,10 @@ function runMigrations(db: Database.Database): void {
         db.exec('CREATE INDEX IF NOT EXISTS idx_journey_photos_photo ON journey_photos(photo_id)');
       }
     },
+    // Migration 99: hide_skeletons per-user setting on journey_contributors
+    () => {
+      try { db.exec('ALTER TABLE journey_contributors ADD COLUMN hide_skeletons INTEGER NOT NULL DEFAULT 0'); } catch {}
+    },
   ];
 
   if (currentVersion < migrations.length) {