fix(spells): correct the acid arrow range

PF1e (SRD spells/acid-arrow.md): "Range long (400 ft. + 40 ft./level)" - the JSON declared medium. Fixed to long. The spell's ongoing acid (2d4 per extra round, one per three caster levels, unless neutralized) is not modeled: the engine has no per-spell damage-over-time subsystem, documented in README rather than built.

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

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

README.md

@@ -1300,6 +1300,13 @@ projectiles multiples, ni sauvegarde partielle) :
   sort est modélisé en dégâts fixes `1d4` feu, sauvegarde de Réflexes pour
   moitié, sur la cible résolue (la formule `1d4+1` qui surestimait le dégât de
   base a été corrigée — conformance D6).
+- **Acid Arrow — sans dégâts continus** (SRD spells/acid-arrow.md : portée
+  **longue** — corrigée, conformance D7 — et « For every three caster levels
+  you possess, the acid, unless neutralized, lasts for another round [...],
+  dealing another 2d4 points of damage in each round ») : le moteur n'a pas de
+  subsystem de dégâts continus par sort (ni neutralisation d'acide) ; seuls les
+  2d4 de dégâts initiaux sont modélisés, les rounds de dégâts persistants sont
+  hors périmètre.
 
 ## Architecture
 

data/spells/acid_arrow.json

@@ -2,7 +2,7 @@
   "name": "Acid Arrow",
   "level": 2,
   "school": "evocation",
-  "range": "medium",
+  "range": "long",
   "save": "none",
   "base_dc": 10,
   "requires_ranged_touch": true,
@@ -15,5 +15,5 @@
       "half_on_save": false
     }
   ],
-  "description": "An arrow of acid springs from your hand and speeds to its target, dealing 2d4 points of acid damage. No save."
+  "description": "SRD spells/acid-arrow.md: ranged touch attack dealing 2d4 acid damage, plus another 2d4 per round for 1 extra round per three caster levels (max 6 additional rounds). The engine has no damage-over-time subsystem, so only the initial 2d4 is modeled - the ongoing acid is documented as a limitation. No save."
 }