chore(charts,errors): apply the tap-target floor across charts and error chrome

Final surface sweep for the v1.4.27 tap-target work: the chart band
overlay, the error-details action row, and the public-page header
links.

- `health-chart.tsx`: band overlay used to inset `right: 18px` while
  the underlying ComposedChart margin is `right: 8`, so the colour
  band drifted left of the plotted line by 10 px on every viewport.
  Pin the overlay to the chart's actual right edge.
- `error-details.tsx`: drop `size="sm"` from the retry, copy, and
  report-issue buttons so they sit at the default 40 px primitive
  height — clears the WCAG 2.5.5 floor on touch.
- `auth/login/page.tsx`: back-to-passkey toggle wraps in `inline-flex
  min-h-11 w-full` so the form-mode swap is reachable on touch.
- `privacy/page.tsx` and `about/page.tsx`: header HealthLog + Sign-in
  links wrap in `inline-flex min-h-11` so the public-page chrome
  clears the floor.

src/components/charts/health-chart.tsx

@@ -1172,11 +1172,17 @@ export function HealthChart({
       ) : (
         <div className={`relative ${chartHeightClass}`}>
           {visibleBands.length > 0 ? (
+            // v1.4.27 R3d MB2 — band overlay positioning fix. The
+            // overlay used to inset `right: 18px` while the chart
+            // margin is `right: 8`, so the band rectangle drifted left
+            // of the plotted line by 10 px on every viewport. Pin the
+            // overlay to the same right edge the ComposedChart uses so
+            // the band tracks the line exactly.
             <div
               className="pointer-events-none absolute"
               style={{
                 left: `${8 + yAxisWidth}px`,
-                right: "18px",
+                right: "8px",
                 top: "10px",
                 bottom: "32px",
                 zIndex: 0,

src/components/error-details.tsx

@@ -84,12 +84,12 @@ export function ErrorDetails({
       </div>
       <div className="flex flex-wrap items-center gap-2">
         {reset && (
-          <Button onClick={reset} variant="outline" size="sm">
+          <Button onClick={reset} variant="outline">
             <RotateCcw className="mr-2 h-4 w-4" />
             {t("common.retry")}
           </Button>
         )}
-        <Button onClick={handleCopy} variant="outline" size="sm">
+        <Button onClick={handleCopy} variant="outline">
           {copied ? (
             <CheckCircle2 className="text-dracula-green mr-2 h-4 w-4" />
           ) : (
@@ -98,7 +98,7 @@ export function ErrorDetails({
           {copied ? t("common.copied") : t("common.copyDetails")}
         </Button>
         {bugReportEnabled && (
-          <Button asChild variant="outline" size="sm">
+          <Button asChild variant="outline">
             <Link href={reportHref}>
               <Bug className="mr-2 h-4 w-4" />
               {t("common.reportIssue")}