v0.8.0

What's New

Numerical Force Models

astroz now includes high fidelity force models for orbit propagation, all implementing a
common ForceModel interface:

• Zonal harmonics: J2, J3, and J4 Earth oblateness perturbations
• Atmospheric drag: Exponential density model with solar activity scaling
• Solar radiation pressure: Includes cylindrical Earth shadow model
• Composite model: Combine multiple force models into a single propagation pipeline

Dormand-Prince 8(7) Adaptive Integrator

A new high order adaptive step size integrator (DormandPrince87) for long duration,
high accuracy propagation. Configurable absolute and relative tolerances, and compatible
with all force models.

CSPICE Integration

Optional NAIF CSPICE bindings (enabled with -Denable-cspice=true) for high precision
planetary ephemeris and leap second handling. Planetary kernels are fetched automatically
at build time.

New Examples

• conjunction_screening.zig — Collision avoidance screening
• maneuver_planning.zig — Hohmann transfers with J2 effects
• constellation_phasing.zig — RAAN drift for Walker constellations
• spice_propagation.zig — High-precision propagation with CSPICE ephemeris

What's Changed

• FEAT: new numerical models by @ATTron in #71
• new Io.Timestamp fix by @ATTron in #72
• bug: remove sdist and license warning by @ATTron in
  #74

Full Changelog: v0.7.1...v0.8.0