fix (ship): clamp arcsin argument to [-1, 1] with np.clip to prevent NaN

[vaaiiibbhav]

Floating-point rounding could push arg_arcsin in get_apparent_wind slightly outside the valid domain of np.arcsin. The previous manual check only clamped the upper bound, so values marginally below -1 produced silent NaNs that corrupted apparent wind angles and downstream fuel/route metrics. Replace the one-sided check with a two-sided np.clip.

Fixes #170

Related Issue / Discussion:

Fixes Issue #170

Changes:

• Modified WeatherRoutingTool/ship/direct_power_boat.py — Replaced the manual one-sided upper bound check for arg_arcsin inside get_apparent_wind() with a robust two-sided np.clip.

Further Details:

Summary:

• Motivation & Context: In get_apparent_wind(), floating-point rounding errors occasionally pushed the argument for np.arcsin() slightly outside the strict math domain of [-1, 1]. While an existing manual check handled the upper threshold, values slightly falling below -1 bypassed it, generating silent NaN values that cascaded down into critical ship routing and fuel consumption metrics.
• Before: The code evaluated a manual difference condition (diff_to_one) that only protected against exceeding the upper bound of 1.0.
• After: Replaced with np.clip(arg_arcsin, -1 * u.radian, 1 * u.radian), ensuring absolute two-sided domain safety while cleanly preserving the astropy.units Quantity wrapper.

Dependencies:

• No new dependencies are required for this modification.

PR Checklist:

• have (already previously) filled the 52North Contributor License Agreement and received positive feedback on this matter
• have filled the 52North Contributor License Agreement and am waiting for feedback
• provide unit tests embedded in the WRT test framework (WeatherRoutingTool/tests) that allow the simple testing of the new/modified functionalities. All (previous and new) unit tests execute without new error messages.
• ensure that the code formatter runs without errors/warnings
• ensure that my changes follow the WRT’s guidelines for contributing at the time of the contribution