Add unit tests for ShortenWaveForFFTIfRequired

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Description

The ShortenWaveForFFTIfRequired function lacked direct unit tests despite implementing non-trivial logic: prime-factor analysis, cached GetGoodFFTSizes lookup, and wave truncation when max prime factor exceeds 1000.

Added four test functions to UTF_Utils_Algorithm.ipf:

• Pass-through behavior: Waves with good FFT sizes (only 2 and 3 as prime factors) return unchanged

  • Tests power of 2, power of 3, and mixed factor cases (1024, 729, 72, 3072)

• Truncation logic: Waves with prime factors >1000 are truncated to nearest good FFT size

  • Verifies size reduction, content preservation, and wave property maintenance
  • Tests with primes 1009, 2017, and 5003

• Cache mechanism: Validates GetGoodFFTSizes caching

  • First call populates cache, subsequent calls reuse cached data
  • Verifies consistent truncation results across calls

• Result validation: Truncated waves have max prime factor ≤1000

  • Tests with multiple sizes (1009, 3001, 10007) to ensure good FFT properties

All tests follow existing patterns in the test suite using standard CHECK macros.

Merge Conflict Resolution

Resolved merge conflicts with the base branch bugfix/2362-psx-support-multiple-selections:

• UTF_Utils_Algorithm.ipf: Preserved test additions (no actual conflict, base branch simply didn't have the tests yet)
• MIES_WaveDataFolderGetters.ipf: Fixed documentation comment order for fastTau/slowTau to match the actual implementation (columns 10 and 11)

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[t-b]

@copilot Please resolve conflicts.

[Copilot]

@copilot Please resolve conflicts.

Resolved merge conflicts in commit a6c47d4. The conflicts were:

• UTF_Utils_Algorithm.ipf: Kept test additions (simple addition, no actual conflict)
• MIES_WaveDataFolderGetters.ipf: Kept correct comment order for fastTau/slowTau columns matching the implementation

[Copilot]

Pull request overview

Adds direct unit tests for ShortenWaveForFFTIfRequired, covering pass-through vs truncation behavior and related FFT-size expectations.

Changes:

• Adds pass-through tests for “already acceptable” sizes.
• Adds truncation tests for sizes with max prime factor > 1000, including content preservation checks.
• Adds tests intended to cover cache behavior and “good FFT size” results.

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