Configurable Digital Crown slide navigation with sensitivity and enable toggle

[donny-son]

Motivation

• Prevent accidental slide changes from minor crown movements by accumulating detents before changing slides.
• Provide configurable sensitivity and an option to disable crown navigation so users can tailor behavior to their needs.
• Surface crown-related settings in the app UI and provide contextual help text describing direction and sensitivity.

Description

• Added state and AppStorage properties crownDetentAccumulator, crownControlEnabled, and crownDetentsPerSlide to manage crown behavior and persistence.
• Refactored crown handling into a new handleCrownChange(_:) method that accumulates detent deltas, respects invertCrown, requires crownDetentsPerSlide detents per slide change, and emits haptics on slide transitions.
• Reset the accumulator when crownDetentsPerSlide changes via an onChange handler, and preserved previous detent tracking in lastCrownDetent.
• Extended SettingsView with a Crown Control toggle, a Sensitivity picker (Fast, Balanced, Deliberate, Locked-in), and a computed footer string crownFooterText; the sensitivity controls are disabled when crown control is off.

Testing

• No automated tests were added or run for this change.

---

Codex Task