fix(walking): correct OPC grid layout (2x2) and highlight stages

- OPC: 2x2 grid for 171/65/24/10, highlight 24 (finalists)
- WAIC: highlight 160 (shortlisted) not 30

Author: Zaosusu

src/pages/WalkingXiuxian.tsx

@@ -241,7 +241,7 @@ export function WalkingXiuxian() {
               <p className="font-noto text-sm text-text-secondary leading-relaxed mb-4 flex-grow">{c.waicDesc}</p>
               <div className="grid grid-cols-2 gap-2 mb-4">
                 {c.waicSteps.map((step, i) => (
-                  <div key={step.count} className={`p-2 rounded border text-center ${i === 2 ? 'border-[#6cbcb2]/70 bg-[#6cbcb2]/10' : 'border-border-custom bg-bg-primary/70'}`}>
+                  <div key={step.count} className={`p-2 rounded border text-center ${i === 1 ? 'border-[#6cbcb2]/70 bg-[#6cbcb2]/10' : 'border-border-custom bg-bg-primary/70'}`}>
                     <span className="font-inter font-bold text-xl text-text-primary">{step.count}</span>
                     <p className="font-noto text-xs text-text-secondary mt-1">{step.label}</p>
                   </div>
@@ -275,9 +275,9 @@ export function WalkingXiuxian() {
               </div>
               <h3 className="font-noto font-bold text-lg text-text-primary mb-2">{c.opcTitle}</h3>
               <p className="font-noto text-sm text-text-secondary leading-relaxed mb-4 flex-grow">{c.opcDesc}</p>
-              <div className="grid grid-cols-3 gap-2 mb-4">
+              <div className="grid grid-cols-2 gap-2 mb-4">
                 {c.opcSteps.map((step, i) => (
-                  <div key={step.count} className={`p-2 rounded border text-center ${i === 1 ? 'border-[#6cbcb2]/70 bg-[#6cbcb2]/10' : 'border-border-custom bg-bg-primary/70'}`}>
+                  <div key={step.count} className={`p-2 rounded border text-center ${i === 2 ? 'border-[#6cbcb2]/70 bg-[#6cbcb2]/10' : 'border-border-custom bg-bg-primary/70'}`}>
                     <span className="font-inter font-bold text-xl text-text-primary">{step.count}</span>
                     <p className="font-noto text-xs text-text-secondary mt-1">{step.label}</p>
                   </div>