mobile: textarea text-base on mobile to suppress iOS Safari zoom-on-focus

Five textareas in the app (Coach composer, bug-report description,
admin feedback note, medication-side-effects notes, medication-intake
JSON import) shipped `text-sm` (14 px) on every viewport. iOS Safari
triggers a viewport zoom-on-focus whenever an input renders text
below 16 px — so every tap on these surfaces yanked the page scale
and rebounded on blur. Switched each className to `text-base sm:text-sm`
so the mobile baseline clears 16 px while desktop keeps the compact
look the rest of the form chrome converged on.

No shared <Textarea> primitive exists yet — F-5's deferred work — so
the fix is per-call-site. Five files, one className change each, no
component re-shape.

src/components/admin/feedback-inbox-section.tsx

@@ -501,7 +501,9 @@ function FeedbackDetailDialog({
               rows={3}
               maxLength={5000}
               placeholder={t("admin.feedback.adminNotePlaceholder")}
-              className="border-input bg-background text-foreground placeholder:text-muted-foreground focus-visible:ring-ring w-full rounded-md border px-3 py-2 text-sm focus-visible:ring-2 focus-visible:outline-none"
+              // text-base on mobile so iOS Safari doesn't zoom on
+              // focus; text-sm on sm+ keeps the compact admin look.
+              className="border-input bg-background text-foreground placeholder:text-muted-foreground focus-visible:ring-ring w-full rounded-md border px-3 py-2 text-base focus-visible:ring-2 focus-visible:outline-none sm:text-sm"
             />
             <div className="flex justify-end">
               <Button