v0.9.3

• Added: Comprehensive preflight input validation to check model parameters
  and report actionable errors before calculations start in GUI and batch modes.
• Fixed: Resolved NaN propagation in CompatibleRvtMotion when calculation
  frequencies exceed target spectrum range.
• Changed: Reflowed the General Settings page into three columns to reduce
  vertical space on laptop screens.
• Fixed: Duplicated entries (e.g. 6 instead of 3) in the "Type" drop-down of
  the Input Motions table.
• Fixed: example-08.json regression example failed the new preflight
  validation because its RVT motion's frequency array was rounded to only
  ~3 significant figures, producing non-increasing values. Regenerated the
  frequency array from its exact log-spaced values and the corresponding
  Fourier amplitudes with a smoothing fit, restoring full precision.