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/components/detail/detail-case-studies-section.tsx

@@ -68,7 +68,7 @@ export function CaseStudiesSection({
 
         {/* grid 直接挂 StaggerReveal（见文件头注释），gap-px 露出容器底色形成发丝分隔线 */}
         <StaggerReveal
-          staggerDelay={0.1}
+          staggerDelay={0.05}
           delayChildren={0.05}
           className="grid md:grid-cols-2 lg:grid-cols-3 gap-px bg-border-primary"
         >

src/components/detail/detail-certifications-section.tsx

@@ -50,7 +50,7 @@ export function CertificationsSection({ certifications }: CertificationsSectionP
 
         {/* flex 直接挂 StaggerReveal（同 CaseStudiesSection 的布局要点） */}
         <StaggerReveal
-          staggerDelay={0.08}
+          staggerDelay={0.05}
           delayChildren={0.05}
           className="flex flex-wrap justify-center gap-px bg-border-primary"
         >

src/components/detail/detail-hero.tsx

@@ -54,7 +54,7 @@ export function DetailHero({
             visible: {
               transition: {
                 staggerChildren: 0.12,
-                delayChildren: 0.2,
+                delayChildren: 0.05,
               },
             },
           }}