ui(motion): TabStrip Reduced should cubic-animate indicator (not snap)

[ZhuchkaTriplesix]

Parent

Part of epic #490.

Problem

QueryaSpring.springsEnabled is Full-only (correct after #481). When springs are off, QueryaSpringController uses jumpTo — so under Reduced the tab pill snaps. Preferences copy says Reduced halves durations, not “disable slides.”

Affects workspace homes + Extension Manager.

Proposal

• Full → springs (unchanged)
• Reduced → duration-token cubic move of indicator (fast/standard via effectiveDuration)
• Off / OS disableAnimations → snap

Files

• lib/shared/widgets/querya_tab_strip.dart
• lib/core/motion/querya_spring_controller.dart (if shared)

Acceptance

• Reduced: pill slides with halved duration
• Off: still instant
• Full: still spring / redirectable

[ZhuchkaTriplesix]

Shipped on dev (PR targeted dev, auto-close did not fire).