Remove the entire Angry Birds implementation including physics solver,
game logic, Phaser scene, level data, verification tool, and registry
wiring. Also delete the build-plan documentation.
Meanwhile, upgrade Goo Tower rendering: spikes now have faceted steel
teeth with dynamic lighting, rust speckling, and twinkling glints;
lava features layered heat gradients, animated flow streaks, and
rising bubbles. Update gootower levels 6-7 and zuma level 6.
