Particle effects: falling trails behind projectiles, exploding fireballs and cannonballs, arrows stuck in walls and floors

- projectiles get styles: arrows (shaft and fletching), cannonballs and fireballs fly in an arc, shadow, holy, arcane, rune and magic bolts with their own glow
- trails of embers, sparks, motes or smoke that drift down to the floor
- fireballs explode on the ground (flash, shock wave, embers, smoke, scorch mark), cannonballs burst into stones, dirt, sparks and smoke
- arrows stay stuck in walls (or glance off into the floor) for five minutes, at most 400; they drop out when the wall is dug away
- spells: lightning sprays sparks and scorches the floor, healing lifts green motes, level-ups and summoning rain sparkles; digging throws earth, gold pops coins
- particles are never saved and use their own random numbers

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/main.rs

@@ -12,6 +12,7 @@ mod i18n;
 mod map;
 mod menu;
 mod platform;
+mod particles;
 mod props;
 mod rival;
 mod render3d;