refactor(animations): converge P2 stagger delays to ≤60ms target

Task #16 P2: converge 25 stagger/delay delays to ≤60ms target.

scope: 12 files, 25 staggerDelay/delayChildren props
before: 0.07/0.08/0.1/0.12s -> after: 0.05s (50ms, aligns ScrollReveal default)

verified:
- tsc --noEmit: clean (TSC_EXIT=0)
- eslint (12 files): 0 errors, 22 pre-existing warnings only
- jest: 130/130 suites, 1573 passed, 2 skipped, 0 failed (JEST_EXIT=0)
- motion audit: P0=0, P1=5 preserved, P2=0, OK=425

note: P1 residual 5 preserved (flip-clock 2 + page-transition 2 by
semantics; design-system.ts 1 dead-code deferred). visual regression
waived: stagger is entrance delay, reducedMotion yields same pixels.

Co-Authored-By: 阿睿 <workbuddy@local>

src/app/(marketing)/home-content-v15.tsx

@@ -358,7 +358,7 @@ function TrustSection({ pageCopy }: { pageCopy?: HomePageCopy | null }) {
         </div>
 
         {/* 首批客户共创计划：如实呈现共创/内测/授权公开状态，不虚构客户 */}
-        <StaggerReveal staggerDelay={0.08}>
+        <StaggerReveal staggerDelay={0.05}>
           <div className="p-6 sm:p-8 bg-brand-bg border border-[rgba(196,30,58,0.15)]" data-testid="early-access-banner">
             <div className="flex items-center gap-3 mb-4">
               <span className="text-[13px] tracking-[0.12em] font-semibold text-brand">
@@ -439,7 +439,7 @@ function NarrativeSection({ pageCopy }: { pageCopy?: HomePageCopy | null }) {
 
         <div className="grid md:grid-cols-3 gap-px bg-border-primary">
           {NARRATIVE_ACTS_CMS.map((act) => (
-            <StaggerReveal key={act.number} staggerDelay={0.08}>
+            <StaggerReveal key={act.number} staggerDelay={0.05}>
               <div className="group relative h-full bg-bg-primary p-8 sm:p-10 md:p-12 transition-colors duration-300 hover:bg-bg-secondary">
                 <div className="flex items-start justify-between mb-8">
                   <span
@@ -517,7 +517,7 @@ function InsightsSection({ pageCopy }: { pageCopy?: HomePageCopy | null }) {
 
         <div className="grid grid-cols-1 md:grid-cols-2 gap-px bg-border-primary border border-border-primary">
           {items.slice(0, 4).map((insight, i) => (
-            <StaggerReveal key={i} staggerDelay={0.07}>
+            <StaggerReveal key={i} staggerDelay={0.05}>
               <a
                 href={insight.href}
                 className="group flex flex-col h-full bg-bg-primary p-8 sm:p-10 md:p-12 transition-colors duration-300 hover:bg-bg-secondary"