Document haptic timing constants with rationale and performance tradeoffs

[Copilot]

Addresses feedback on PR #8 regarding undocumented magic numbers for haptic timing parameters.

Changes

• UPDATE_INTERVAL_MS (8ms): Documents reduction from 10ms → 8ms (100 Hz → 125 Hz) for improved temporal resolution in fast-changing haptic effects (vibration, pain pulses)

• SUBMISSION_DURATION_MS (100ms): Documents increase from 40ms → 100ms to maintain 12.5x frame overlap, preventing perceptible gaps while balancing responsiveness to rapid intensity changes

// Worker thread update rate: 8ms = 125 Hz
// Reduced from 10ms (100 Hz) to 8ms for smoother haptic feedback and better temporal resolution.
// Higher update rates provide more responsive haptic effects, particularly for fast-changing
// sensations like vibration and pain pulses.
private const int UPDATE_INTERVAL_MS = 8;

// Haptic frame duration: how long each submitted frame persists on the device
// Increased from 40ms to 100ms to ensure smooth overlap between frames and prevent gaps.
// The 100ms duration (with 8ms updates) provides ~12.5x frame overlap, creating seamless
// haptic transitions. Too short a duration can cause perceptible stuttering or dropouts,
// while too long can reduce responsiveness to rapid intensity changes.
private const int SUBMISSION_DURATION_MS = 100;

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