Add GesturePhaseQueue and RingBuffer implementation

[Kyle-Ye]

Summary

Replace the old ConflictResolution/GesturePhaseQueue (untyped entry queue) with a generic GesturePhaseQueue<Value> backed by a fixed-capacity RingBuffer.

• RingBuffer<Element> — generic circular buffer with Collection, BidirectionalCollection, Sequence, and CustomStringConvertible conformances. Default capacity verified from binary as 5 (mov w0, #0x5 at 0x852E4).
• GesturePhaseQueue<Value> — holds timeSource, currentPhase, and pendingPhases: RingBuffer<GesturePhase<Value>>. Includes InvalidTransition error type with NestedCustomStringConvertible.
• GestureNode<Value>.phaseQueue replaces the old phase / latestPhase stored properties.
• Adds 23 new tests: 17 for RingBuffer (init, append, overflow/wrap-around, removeFirst, Collection, Iterator, description) and 6 for GesturePhaseQueue (init, properties, InvalidTransition).

Test plan

• swift test --filter OpenGesturesTests — 48 tests in 8 suites pass
• OPENGESTURES_COMPATIBILITY_TEST=0 swift test --filter OpenGesturesCompatibilityTests

[codecov-commenter]

Codecov Report

❌ Patch coverage is 92.23744% with 17 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.62%. Comparing base (7ed2c4a) to head (cd8e182).

Files with missing lines	Patch %	Lines
Sources/OpenGestures/GestureNode/GestureNode.swift	0.00%	17 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #14      +/-   ##
==========================================
+ Coverage   74.19%   77.62%   +3.43%     
==========================================
  Files          62       65       +3     
  Lines        1519     1712     +193     
==========================================
+ Hits         1127     1329     +202     
+ Misses        392      383       -9     

Flag	Coverage Δ
ios	71.82% <75.71%> (+1.63%)	⬆️
macos	77.62% <92.23%> (+3.43%)	⬆️

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