polish: clear 33/34 detector findings (bg-black, animate-bounce, spinner, transition-width, color)

After re-audit/critique cycle the deterministic detector (npx impeccable)
flagged 34 design-spec violations. Knock out 33 of them.

  • 25 × pure-black-white: sed-sweep bg-black/X → bg-dark-950/X across
    18+ files (modal scrims, photo viewer backdrop, code blocks). The
    base resolves to rgba(10,15,26,X) — visually identical to true
    black, satisfies the 'no #000' impeccable rule.
  • 3 × bounce-easing: SuccessNotificationModal celebration icon and
    SyncTab loading arrows used animate-bounce; replaced with
    animate-pulse. Bounce easing reads dated; pulse conveys 'in
    progress' without the cartoon feel.
  • 3 × border-accent-on-rounded: TelegramCallback + VerifyEmail
    spinners used 'border-b-2 border-accent-500' on rounded-full —
    detector reads it as a side-stripe even though it's a ring loader.
    Switch to canonical 'border-2 border-accent-500 border-t-transparent'
    (3/4 ring colored). Same visual, no spec violation.
  • 1 × ai-color-palette: AdminLandingStats had text-purple-400 on a
    gift-stats heading; purple is not in the brand palette. Swap to
    text-accent-400.
  • 1 × layout-transition: TrafficProgressBar.tsx fill bar still used
    transition: width 1.2s (slipped past the earlier optimize pass).
    Convert to transform: scaleX with origin-left. Same gradient, same
    duration, runs on the compositor.

Remaining: 1 finding in third-party Aceternity background-beams-collision
component (indigo-500 gradient on decorative WebGL background) — left
as-is, it's lifted decorative third-party code.

Detector: 34 → 1.

src/pages/Support.tsx

@@ -346,7 +346,7 @@ export default function Support() {
               </div>
             )}
             {att.uploading && (
-              <div className="absolute inset-0 flex items-center justify-center rounded-lg bg-black/50">
+              <div className="absolute inset-0 flex items-center justify-center rounded-lg bg-dark-950/50">
                 <span className="h-4 w-4 animate-spin rounded-full border-2 border-accent-500 border-t-transparent" />
               </div>
             )}