perf(motion): 第三批入场动效时长收敛至 300ms（9 文件 20 处）

承接前两批，继续清理 Task #16 的 P0 硬违规：

- brand-content (1) / methodology-content (3) / products-content-v3 (4) /
  solution-detail-content-v3 (4) / team-content-v3 (1) / detail-product-value (2) /
  service-value (1) / solution-value (3) / brand-visuals 入场处 (1)
- 审计：P0 33 → 13，P1 163 / P2 28 持平
- 只改 duration，保留原 delay（与首批先例一致）

验证：
- tsc --noEmit 0 error；eslint 9 文件 0 error（仅 methodology 既有 `any` 警告，非本次引入）
- 视觉基线不变：前两批已证明时长改动在 reducedMotion+animations disabled 下不改变最终像素

剩余 13 处 P0 均为决策点，未在本批处理：
- 3 处循环动画（detail-hero ×2、brand-visuals ×1，repeat:Infinity，违反「禁循环动画」）
- 10 处死代码（src/lib/animations.tsx，全站零引用）

src/app/(marketing)/solutions/solution-detail-content-v3.tsx

@@ -45,7 +45,7 @@ function DetailHero({ solution }: DetailHeroProps) {
         <motion.div
           initial={{ opacity: 0, y: 30 }}
           animate={{ opacity: 1, y: 0 }}
-          transition={{ duration: 0.8, ease: EASE_OUT }}
+          transition={{ duration: 0.3, ease: EASE_OUT }}
           className="flex items-center gap-4 mb-8"
         >
           <div className="w-16 h-16 rounded-2xl bg-brand-soft flex items-center justify-center text-brand">
@@ -62,7 +62,7 @@ function DetailHero({ solution }: DetailHeroProps) {
         <motion.h1
           initial={{ opacity: 0, y: 50 }}
           animate={{ opacity: 1, y: 0 }}
-          transition={{ duration: 1, delay: 0.15, ease: EASE_OUT }}
+          transition={{ duration: 0.3, delay: 0.15, ease: EASE_OUT }}
           className="text-3xl sm:text-4xl md:text-5xl lg:text-6xl font-bold text-ink leading-tight tracking-tighter mb-6 sm:mb-8 max-w-4xl"
         >
           {solution.title}
@@ -71,7 +71,7 @@ function DetailHero({ solution }: DetailHeroProps) {
         <motion.p
           initial={{ opacity: 0, y: 40 }}
           animate={{ opacity: 1, y: 0 }}
-          transition={{ duration: 0.9, delay: 0.3, ease: EASE_OUT }}
+          transition={{ duration: 0.3, delay: 0.3, ease: EASE_OUT }}
           className="text-xl lg:text-2xl text-text-secondary max-w-3xl leading-relaxed mb-12"
         >
           {solution.description}
@@ -80,7 +80,7 @@ function DetailHero({ solution }: DetailHeroProps) {
         <motion.div
           initial={{ opacity: 0, y: 40 }}
           animate={{ opacity: 1, y: 0 }}
-          transition={{ duration: 0.9, delay: 0.45, ease: EASE_OUT }}
+          transition={{ duration: 0.3, delay: 0.45, ease: EASE_OUT }}
           className="flex flex-wrap gap-6"
         >
           <CTAButton href="/contact" dataTestId="solution-detail-hero-primary">