Motivation

Replace the legacy ProgressBar and ActivityIndicator with a token-driven
Material Design 3 progress indicator family. Four components cover the
linear and circular shapes, each in a standard and an expressive "wavy"
variant, with determinate and indeterminate modes.

• Add LinearProgressIndicator and CircularProgressIndicator (standard)
  and LinearWavyProgressIndicator and CircularWavyProgressIndicator
  (expressive wave), built on react-native-svg with shared spec tokens.
• progress accepts a number or a Reanimated SharedValue<number>, so a
  caller-animated value glides on the UI thread with no re-renders.
• Indeterminate timing follows the MD3 motion spec (linear spin + breathing
  sweep for circular; two-segment travel for linear).
• Wavy variants animate a traveling wave that flattens near 0% and 100%;
  amplitude, wavelength, and waveSpeed are configurable. Wave geometry
  is computed in worklets (wavePath.ts).
• Migrate the internal loading spinner in Button, IconButton, and Searchbar
  to the standard indeterminate CircularProgressIndicator.
• Add react-native-svg as a dependency (peer >= 15.0.0).
• Rework the example screen

BREAKING CHANGE: The progress components were redesigned for MD3 with no deprecation aliases.

• ProgressBar and ProgressBarProps are removed. Use
  LinearProgressIndicator (or LinearWavyProgressIndicator). The
  progress prop is the same 0..1 range; indeterminate replaces the old
  indeterminate behavior.
• ActivityIndicator and ActivityIndicatorProps are removed. Use
  CircularProgressIndicator indeterminate.

Related issue

Test plan

• Lint, typescript, existing and new tests pass
• manual visual inspection on all platforms