Simulator: model finite magnetometer range

[tribbloid]

Source: Packages/ARGlassesSDK/__module~/driver/src/sim/TODO.md

Gaussian noise is currently added without a physical sensor range, allowing arbitrarily extreme finite magnetometer readings in long immediate streams.

Acceptance criteria:

• Add a public configurable physical magnetometer range with documented microtesla units.
• Normalize invalid configuration safely.
• Clamp readings or expose saturation when the distorted noisy value exceeds the range; preserve the existing GlassesEvent API.
• Add deterministic tests for positive/negative saturation, defaults, and invalid/boundary configuration.
• Run formatting, checks, tests, and clippy applicable to the driver crate.