fix: react-doctor small categories 68→72 (a11y+perf+style, 21 fixes)

- no-outline-none (2): add focus-visible outline to inline-styled inputs
- no-redundant-roles (2): drop role="list" on <ul>
- click-events-have-key-events (2): convert div backdrops to buttons
- no-static-element-interactions (2): add role+tabIndex+onKeyDown to clickable divs
- rendering-svg-precision (2): round SVG path decimals
- no-tiny-text (2): 11px → 12px on CommandPalette hints
- js-set-map-lookups (4→1): Sets for visibleItems, regex for keyword match
- no-gray-on-colored-background (4): use color-matched text instead of stone-400/900
- no-transition-all (4): list specific properties in transition shorthand

src/components/water/WaterFieldClient.tsx

@@ -555,7 +555,7 @@ function WaterFieldInner() {
             {t.selectHeadgate}
           </label>
           {isHeadgateLocked ? (
-            <div className="w-full rounded-xl border-2 border-amber-300 bg-amber-50 px-4 py-4 text-lg font-bold text-stone-900">
+            <div className="w-full rounded-xl border-2 border-amber-300 bg-amber-50 px-4 py-4 text-lg font-bold text-amber-900">
               <div className="flex items-center gap-2">
                 <svg className="w-5 h-5 text-amber-600" fill="none" viewBox="0 0 24 24" stroke="currentColor" strokeWidth={2}>
                   <path strokeLinecap="round" strokeLinejoin="round" d="M12 15v2m-6 4h12a2 2 0 002-2v-6a2 2 0 00-2-2H6a2 2 0 00-2 2v6a2 2 0 002 2zm10-10V7a4 4 0 00-8 0v4h8z"/>