UI-A1 — Motion tokens core (QueryaMotion)

[ZhuchkaTriplesix]

Epic: #170
Depends on: 0.4.3 shipped

Source: docs/motion-and-high-refresh.md §4

Goal

Introduce lib/core/motion/ as the single source of truth for animation durations and curves across the app.

Files

• lib/core/motion/querya_motion.dart (new)
• lib/core/motion/motion_scope.dart or extension on BuildContext (new)
• test/core/motion/querya_motion_test.dart (new)

Implementation

• Duration tokens: instant (0 ms), fast (120 ms), standard (200 ms), slow (320 ms).
• Curve tokens: enter (easeOutCubic), exit (easeInCubic), standard (easeInOutCubic), emphasized (easeInOutCubicEmphasized).
• Helper effectiveDuration(BuildContext, Duration) that reads MediaQuery.disableAnimationsOf(context) and returns instant when OS reduce-motion is on (A5 will add in-app override later; design API now).
• Export from a small barrel if needed; no widget changes in this issue.

Acceptance Criteria

• All tokens documented in code (brief dartdoc).
• effectiveDuration returns 0 ms when disableAnimations: true in MediaQuery.
• Unit tests cover token values and reduced-motion collapse.
• flutter analyze clean.

Tests

• Token constants match design doc values.
• effectiveDuration with/without MediaQuery.disableAnimations.

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