OpenRocketEngine -> Rocket

[cmflannery]

Summary

Renamed package: openrocketengine → rocket

New rocket.tanks module with:

• Propellant density database (LOX, LH2, RP-1, CH4, N2O4, MMH, etc.)
• Tank material database (Al2219, Al2195, SS301, Ti6Al4V, CFRP)
• size_propellant() - rocket equation calculations
• size_tank() - cylindrical tanks with elliptical domes

Complete vehicle sizing workflow:

from rocket import EngineInputs, design_engine, size_propellant, size_tank
from rocket.units import kilonewtons, megapascals, km_per_second, kilograms

# 1. Design engine from propellants
inputs = EngineInputs.from_propellants("LOX", "CH4", thrust=kilonewtons(500), ...)
perf, geom = design_engine(inputs)

# 2. Size propellant from delta-V
prop = size_propellant(isp_s=perf.isp.value, delta_v=km_per_second(9.5), ...)

# 3. Size tanks
lox_tank = size_tank(prop.oxidizer_mass, "LOX", tank_pressure=pascals(300000))
ch4_tank = size_tank(prop.fuel_mass, "CH4", tank_pressure=pascals(250000))

Tests: 189 passing tests covering all modules

Example output:

• Methalox-500 engine: Isp = 320s (SL) / 347s (vac)
• For 9.5 km/s delta-V: ~103 tons propellant
• LOX tank: 3.3m diameter, 9m long, 597 kg
• CH4 tank: 3.1m diameter, 8.5m long, 420 kg