More realistic GPS simulation with consistent lateral offset

[engali94]

More realistic GPS simulation with consistent lateral offset

Current Behavior

The current simulated location provider follows route coordinates exactly, which doesn't reflect real-world GPS behavior. This makes it difficult to properly test route-snapping and other location-based features under realistic conditions.

Proposed Changes

Add support for simulated GPS inaccuracy by implementing consistent lateral offset from the route line.

[engali94]

Hello @ianthetechie @Archdoog

the idea of this is to add lateral jitter to the simulated location and give the user full control over it by
adding support for configurable GPS bias simulation through a type-safe enum:

pub enum LocationBias {
    Left(f64),  // meters offset to the left of route
    Right(f64), // meters offset to the right of route
    Random(f64), // randomly alternate between left/right with given radius
    None,       // exact route following (current behavior)
}

the end user would use it in this way:

let provider = SimulatedLocationProvider()
// Test left-biased GPS behavior (4 meters to the left)
try provider.setSimulatedRoute(route, resampleDistance: 10, bias: .left(4.0))

// Or test right-biased behavior
try provider.setSimulatedRoute(route, resampleDistance: 10, bias: .right(4.0))

// Or exact route following
try provider.setSimulatedRoute(route, resampleDistance: 10) // Default behavior bias: .none