fix: frontend UI polish — tooltips, planner checkbox, settings layout (#228)

- Fix mobile tooltip positioning (above icon instead of centered)
- Place planner checkbox and send-now button on same row
- Move settings tooltips beside input fields instead of overlapping
- Fix input-with-tooltip layout for narrow screens
- Add daily/everyNDays i18n keys for dose frequency display
- Fix lint formatting in page components

Closes #225

frontend/src/i18n/de.json

@@ -434,6 +434,8 @@
     "of": "von",
     "loose": "lose",
     "none": "Kein",
+    "daily": "täglich",
+    "everyNDays": "alle {{count}} Tage",
     "day": "Tag",
     "days": "Tage",
     "blister": "Blister",