Clear the accessibility findings on about, privacy, achievements, cycle and admin

Inline links on the prose pages carry an underline and their body copy
reads in the content colour, so the links no longer rely on colour alone
and the code chips meet contrast. Locked achievements drop the opacity
that pushed their text below AA. The cycle calendar nests its headers and
day cells in ARIA rows, the login overview's page-size select is named,
and the measurement type badges take a lighter wash in the light theme so
their label holds 4.5:1.

src/components/admin/login-overview-section.tsx

@@ -328,7 +328,10 @@ export function LoginOverviewSection() {
         {/* Toolbar row: per-page + export */}
         <div className="flex flex-wrap items-center justify-between gap-2">
           <div className="flex items-center gap-2 text-xs">
-            <span className="text-muted-foreground">
+            <span
+              id="login-overview-per-page"
+              className="text-muted-foreground"
+            >
               {t("admin.section.auditLog.perPage")}
             </span>
             <Select
@@ -338,7 +341,10 @@ export function LoginOverviewSection() {
                 setPerPage(Number(v) as PerPageValue);
               }}
             >
-              <SelectTrigger className="h-8 w-20">
+              <SelectTrigger
+                className="h-8 w-20"
+                aria-labelledby="login-overview-per-page"
+              >
                 <SelectValue />
               </SelectTrigger>
               <SelectContent>