Add flaps: flappable tag, flap lever on the control node, flap physics (0.4.0)

Shift-right-click a block in improved_aerodynamics:flappable to make it a flap.
G/H step the node's flap lever UP/TAKEOFF/LANDING; flaps slew to the configured
angle, add lift and drag and raise the stall angle, and retract above a max speed.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YVREx3uo7nz1FEhzveWTUh

gradle.properties

@@ -12,7 +12,7 @@ mapping_version=2023.09.03-1.20.1
 mod_id=improved_aerodynamics
 mod_name=VS: Improved Aerodynamics
 mod_license=MIT
-mod_version=0.3.0
+mod_version=0.4.0
 azurelib_version=3.2.7
 mod_group_id=dev.lumareth.improvedaerodynamics
 mod_authors=Lumareth