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/ui/page-transition.tsx

@@ -102,7 +102,7 @@ export function StaggerChildren({
         visible: {
           transition: {
             staggerChildren: 0.06,
-            delayChildren: 0.1,
+            delayChildren: 0.05,
           },
         },
       }}