fix(mobile): hit WCAG 2.5.5 44 px touch-target floor across top-bar + section strips

Pixel-5 (393 px) audit flagged four primary navigation surfaces that
were below the 44 px touch-target floor:

  - TopBar user-menu trigger and login link: text-only flex with
    py-1.5 measured ~30 px tall. Added min-h-11 min-w-11 with a
    rounded hit zone so the trigger lands on the WCAG floor without
    visibly altering the icon's position.

  - SettingsShell mobile section chip-strip and AdminShell mobile
    section chip-strip: rounded-full chips with py-1.5 were ~30 px
    tall. The mobile chip-strips are the primary navigation surface
    for /settings and /admin on touch devices, so min-h-11 was added
    to both.

  - medication-form schedule interval picker (1W / 2W / 3W / 4W):
    h-8 native buttons inside a 4-col grid; min-h-11 brings them up
    to the floor without changing column width.

Also normalised the medications page-root spacing from space-y-5 to
space-y-6 to match dashboard / measurements / mood / notifications.

src/app/medications/page.tsx

@@ -120,7 +120,7 @@ export default function MedicationsPage() {
 
   if (!isAuthenticated) {
     return (
-      <div className="space-y-5">
+      <div className="space-y-6">
         <div className="space-y-1">
           <h1 className="text-2xl font-bold tracking-tight">
             {t("medications.title")}
@@ -143,7 +143,7 @@ export default function MedicationsPage() {
   const inactiveMeds = medsArray.filter((m) => !m.active).sort(byName);
 
   return (
-    <div className="space-y-5">
+    <div className="space-y-6">
       <div className="flex items-start justify-between gap-3">
         <div className="space-y-1">
           <h1 className="text-2xl font-bold tracking-tight">
@@ -195,7 +195,7 @@ export default function MedicationsPage() {
           }
         />
       ) : (
-        <div className="space-y-5">
+        <div className="space-y-6">
           {/* Active medications */}
           {activeMeds.length > 0 && (
             <div className="space-y-3.5">