feat(polish): wire haptics, sounds, and animation into feature views

[dinesh-git17]

Summary

Implements E8.2: Wire Haptics, Sounds, and Animation Polish. Integrates sound triggers, haptic feedback, and motion polish into four feature views per design doc S6.6, S6.8, and S3.7.

Design Doc Alignment

• S6.6: Signature reveal (0.5s ease, 0.95-1.0 scale), card parallax via scroll transitions, reduced-motion awareness.
• S6.8: Page-turn sound on completed page transitions, signature-placed sound on successful sign confirmation.
• S3.7: Medium-impact haptic on successful signature confirmation only.
• S6.6 screen transitions: Navigation fade (0.3-0.4s) not implemented. The NavigationStack + UIPageViewController architecture does not safely support custom navigation transitions without regression risk. Deferred to a dedicated navigation polish pass.

Changes

• HomeView.swift: Settings gear button (sheet presentation of SettingsView), ScrollView wrapper with scrollTransition parallax on cards, accessibilityReduceMotion awareness.
• ContractBookView.swift: SoundService environment injection through UIHostingController bridge, soundService.play(.pageTurn) in didFinishAnimating delegate callback (fires only on completed transitions).
• SignaturePadView.swift: UIImpactFeedbackGenerator(style: .medium).impactOccurred() and soundService.play(.signaturePlaced) at the successful sign-confirmation boundary (after hasSubmitted = true, before dismiss()).
• SignatureBlockView.swift: .transition(.opacity.combined(with: .scale(scale: 0.95))) on signature image, withAnimation(.easeInOut(duration: 0.5)) on image load for new signings only. hasPerformedInitialLoad flag prevents re-animation on initial view appearance for already-signed content.

Risk Surface

• Parallax via scrollTransition only activates during actual scroll transitions. On devices where all 3 cards fit on screen, the effect is invisible. Correct behavior -- parallax requires scroll.
• SoundService environment injection through the UIHostingController bridge uses a 4-branch switch for type safety. FinalPageView excluded (no environment needed).
• Haptic fires synchronously on main thread. For <50KB PNG signatures, the save-to-cache async operation completes before the haptic, so no perceptible delay.

Testing

• Built with xcodebuild -project ExhibitA.xcodeproj -scheme ExhibitA -sdk iphoneos build. Zero errors, zero code warnings.
• Protocol Zero scan: PASS.
• Typographic lint: PASS.
• All pre-commit hooks pass.
• UnreadBadge 2-second breathing cadence preserved (no changes to UnreadBadge.swift).

Protocol Zero

./scripts/protocol-zero.sh exits 0.

Typographic Lint

./scripts/check-em-dashes.sh exits 0.

[github-actions]

CI Health Report

Workflow	Status	Notes	Additional Context
Content Validation	✅ success	--	0m 13s
Full Stack Smoke	✅ success	--	0m 28s
PR Governance	✅ success	--	0m 18s
iOS Build & Test	✅ success	--	0m 12s

Not triggered: API Sync Contract, Admin Smoke, Backend Quality, DB Schema Check, Dependabot Updates, Push Mock Integration, Release Readiness, iOS Assets & Theme Check, pages-build-deployment

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_{4 passed | 0 failed | 0 other | Commit: 952f103 | 2026-03-05 04:17:37 UTC}