UI-A5 — Reduced motion and Preferences toggle

[ZhuchkaTriplesix]

Epic: #170
Depends on: #173 (UI-A1)

Source: docs/motion-and-high-refresh.md §4.3

Goal

Honor OS "reduce motion" and add an in-app motion preference in Preferences → Appearance.

Files

• lib/core/motion/querya_motion.dart — extend effectiveDuration with in-app override
• lib/core/storage/app_settings.dart — persist motion preference
• lib/features/settings/preferences_appearance_section.dart — UI control
• test/core/motion/querya_motion_test.dart
• test/features/settings/preferences_appearance_section_test.dart

Implementation

• OS level: MediaQuery.disableAnimationsOf(context) → collapse durations to instant (or minimal cross-fade).
• In-app toggle: Motion — Full / Reduced / Off (stored in AppSettings).
  • Full — use token durations.
  • Reduced — shorten all durations (~50%) or single short cross-fade.
  • Off — instant (0 ms) except essential feedback.
• Wire through QueryaMotion.effectiveDuration / curve helper used by A2/A3 widgets.
• Respect OS reduce-motion even when app setting is Full (OS wins).

Acceptance Criteria

• OS reduce-motion disables long animations app-wide.
• Preferences toggle persists across restart.
• Widget test: disableAnimations: true → 0 ms effective duration.
• flutter analyze clean.

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