feat(rules): support multi-projectile spells

SRD Magic Missile fires one missile +1 per two caster levels beyond 1st (max 5, 1d4+1 force, auto-hit); Scorching Ray fires one ray +1 per four levels beyond 3rd (max 3, 4d6 fire, ranged touch each). DamageEffect gains a ProjectileScaling spec (JSON 'projectiles'); _apply_damage_effect loops count_for(caster_level) projectiles, each rolling its own damage and (for a declared-projectile ray) its own ranged touch attack, with the target-drops-mid-sequence convention losing the rest. Updated magic_missile.json/scorching_ray.json, the golden lich transcript (CL 11 now fires 5 missiles, Tammara dies round 1: 43 damage), the scripted MM queues in test_spells/test_conformance_spellflow, added tests/test_multi_projectile.py, and the README.

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

data/spells/scorching_ray.json

@@ -12,8 +12,9 @@
       "type": "damage",
       "formula": "4d6",
       "types": ["fire"],
-      "half_on_save": false
+      "half_on_save": false,
+      "projectiles": { "base": 1, "per_levels": 4, "at_level": 3, "max": 3 }
     }
   ],
-  "description": "You blast your enemy with a searing beam of fire: each ray requires a ranged touch attack and deals 4d6 points of fire damage. You fire one ray, plus one additional ray per four levels beyond 3rd (max three at 11th) — the engine models a single ray. No save."
+  "description": "SRD spells/scorching-ray.md: a searing beam of fire. One ray, plus one additional ray for every four caster levels beyond 3rd (to a maximum of three rays at 11th level). Each ray requires a ranged touch attack to hit and deals 4d6 points of fire damage. No save."
 }