fix(web): honor reduced-motion preferences across product UI

[jeanduplessis]

Problem

Shared and feature-specific animations use bounce, scale, layout-property transitions, perpetual pulse/ping/spin, and long choreography without prefers-reduced-motion behavior.

Remediation action

Add one consistent reduced-motion policy and apply it to all audited product motion.

Representative scope

• apps/web/src/app/globals.css:423
• apps/web/src/components/ui/sidebar.tsx:227
• apps/web/src/components/HeaderLogo.tsx:33
• apps/web/src/components/cloud-agent-next/TypingIndicator.tsx:12
• apps/web/src/components/app-builder/AppBuilderChat.tsx:132
• apps/web/src/components/code-reviews/CodeReviewStreamView.tsx:620
• apps/web/src/app/(app)/claw/components/ProvisioningStep.tsx:193
• apps/web/src/app/(app)/gastown/onboarding/OnboardingStepModel.tsx:27
• apps/web/src/components/gastown/BeadBoard.tsx:227
• apps/web/src/components/wasteland/WastelandSidebar.tsx:105

Acceptance criteria

• Nonessential bounce, scale, glow, spring, stagger, pulse, ping, and spin stop under reduced motion.
• Functional progress remains understandable through static text/icon state.
• Product transitions target explicit transform/opacity/color properties, use canonical duration/easing, and avoid casual width/height/position animation.
• Legacy glow values and button scaling are removed from global animation.
• Automated or Storybook coverage demonstrates normal and reduced-motion states.