feat(t5): Fokusring für alle, 44-px-Ziele bei Touch, 16-px-Schrift (T5a A5)

- globals.css: eine Basisregel :where(:focus-visible) mit --focus-width
  und --focus-offset (Sonne 3 px), Firefox-:-moz-focusring gleichgezogen;
  --text-xs 0.8125rem.
- Fokus-Codemod (scripts/codemod-t5-focus.mjs): eigene Ringe und
  outline-none raus, sm:h-/sm:size- zu pointer-fine:, Label-Zeilen mit
  focus-ring-within; Skript-Fokus (Lücken-Liste, „Gespeichert“) bleibt.
- Button/Input 44 px, kompakt nur mit Maus; Icon-Knöpfe mit unsichtbarer
  44-px-Trefferfläche bei Touch, Nachbarn mit genug Abstand.
- 16 px in Feldern, Labels, Auswahl, Leerzuständen, Listentiteln.
- .holo-stage auf allen Beute-Bühnen, .stage-card holt den Seitenring.
- Baukasten-Wächter (src/styles/baukasten-guard.spec.ts) mit den Regeln
  aus A3–A5, Ausnahmen mit Grund; Kalender-Auswahl als Inset-Ring.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Frontend/src/components/ui/button.tsx

@@ -3,8 +3,13 @@ import { cva, type VariantProps } from "class-variance-authority"
 
 import { cn } from "@/lib/utils"
 
+// Icon-only buttons get a 44 px hit area under a coarse pointer, centred and invisible, so they
+// stay small on screen but are easy to hit with a thumb or a glove (spec 4.5).
+const HIT_AREA =
+  "relative pointer-coarse:after:absolute pointer-coarse:after:top-1/2 pointer-coarse:after:left-1/2 pointer-coarse:after:size-11 pointer-coarse:after:-translate-1/2"
+
 const buttonVariants = cva(
-  "group/button inline-flex shrink-0 items-center justify-center rounded-xl border border-transparent bg-clip-padding text-sm font-medium whitespace-nowrap transition-all outline-none select-none focus-visible:border-ring focus-visible:ring-3 focus-visible:ring-ring/50 active:not-aria-[haspopup]:translate-y-px disabled:pointer-events-none disabled:opacity-50 aria-invalid:border-destructive aria-invalid:ring-3 aria-invalid:ring-destructive/20 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4",
+  "group/button inline-flex shrink-0 items-center justify-center rounded-xl border border-transparent bg-clip-padding text-sm font-medium whitespace-nowrap transition-all select-none active:not-aria-[haspopup]:translate-y-px disabled:pointer-events-none disabled:opacity-50 aria-invalid:border-destructive aria-invalid:ring-1 aria-invalid:ring-inset aria-invalid:ring-destructive [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4",
   {
     variants: {
       variant: {
@@ -17,24 +22,24 @@ const buttonVariants = cva(
         ghost:
           "hover:bg-muted hover:text-foreground aria-expanded:bg-muted aria-expanded:text-foreground",
         destructive:
-          "bg-destructive/10 text-destructive hover:bg-destructive/20 focus-visible:border-destructive/40 focus-visible:ring-destructive/20",
+          "bg-destructive/10 text-destructive hover:bg-destructive/20",
         link: "text-primary-ink underline-offset-4 hover:underline",
       },
       size: {
-        // Phones get at least 40 px: tapped with a thumb, often with gloves.
+        // 44 px for a thumb (often with gloves); compact only for a mouse or pen.
         default:
-          "h-10 sm:h-8 gap-1.5 px-2.5 has-data-[icon=inline-end]:pr-2 has-data-[icon=inline-start]:pl-2",
+          "h-11 pointer-fine:h-8 gap-1.5 px-2.5 has-data-[icon=inline-end]:pr-2 has-data-[icon=inline-start]:pl-2",
         xs: "h-6 gap-1 rounded-[min(var(--radius-md),10px)] px-2 text-xs in-data-[slot=button-group]:rounded-lg has-data-[icon=inline-end]:pr-1.5 has-data-[icon=inline-start]:pl-1.5 [&_svg:not([class*='size-'])]:size-3",
-        sm: "h-9 sm:h-7 gap-1 rounded-[min(var(--radius-md),12px)] px-2.5 text-[0.8rem] in-data-[slot=button-group]:rounded-lg has-data-[icon=inline-end]:pr-1.5 has-data-[icon=inline-start]:pl-1.5 [&_svg:not([class*='size-'])]:size-3.5",
+        sm: "h-9 pointer-fine:h-7 gap-1 rounded-[min(var(--radius-md),12px)] px-2.5 text-[0.8rem] in-data-[slot=button-group]:rounded-lg has-data-[icon=inline-end]:pr-1.5 has-data-[icon=inline-start]:pl-1.5 [&_svg:not([class*='size-'])]:size-3.5",
         lg: "h-9 gap-1.5 px-2.5 has-data-[icon=inline-end]:pr-2 has-data-[icon=inline-start]:pl-2",
         // 44 px: reliable with gloves or sticky fingers at the apiary.
-        touch: "h-11 gap-2 px-4 text-[0.95rem] [&_svg:not([class*='size-'])]:size-5",
-        icon: "size-8",
+        touch: "h-11 gap-2 px-4 text-base [&_svg:not([class*='size-'])]:size-5",
+        icon: `size-8 ${HIT_AREA}`,
         "icon-xs":
-          "size-6 rounded-[min(var(--radius-md),10px)] in-data-[slot=button-group]:rounded-lg [&_svg:not([class*='size-'])]:size-3",
+          `size-6 rounded-[min(var(--radius-md),10px)] in-data-[slot=button-group]:rounded-lg [&_svg:not([class*='size-'])]:size-3 ${HIT_AREA}`,
         "icon-sm":
-          "size-7 rounded-[min(var(--radius-md),12px)] in-data-[slot=button-group]:rounded-lg",
-        "icon-lg": "size-9",
+          `size-7 rounded-[min(var(--radius-md),12px)] in-data-[slot=button-group]:rounded-lg ${HIT_AREA}`,
+        "icon-lg": `size-9 ${HIT_AREA}`,
       },
     },
     defaultVariants: {