feat(data): transpose Foundry PC sheets into data/pcs

All 8 sheets from fiches_personnages/ converted to the strict Combatant
JSON schema (data/monsters convention) so the CLI can run PCs directly:

  --side players data/pcs/esha.json

- id derived from the file stem; source field points at the original sheet
- oni: placeholder attacks without encoded damage ('une Pioche', 'Weapon')
  left out, documented in notes (pick stats ambiguous light/heavy in the
  rules KB; no identification possible for 'Weapon')
- README: PC section now documents data/pcs usage
- tests: parametrized load check + golden spots for the 8 PC files

data/pcs/jeanne.json

@@ -0,0 +1,66 @@
+{
+  "name": "Jeanne",
+  "level": 4,
+  "size": "Large",
+  "abilities": {
+    "str_score": 18,
+    "dex_score": 14,
+    "con_score": 15,
+    "int_score": 2,
+    "wis_score": 12,
+    "cha_score": 6
+  },
+  "hp_max": 31,
+  "ac": {
+    "total": 23,
+    "touch": 11,
+    "flat_footed": 21
+  },
+  "bab": 3,
+  "initiative_mod": 2,
+  "speed_land_ft": 40,
+  "saves": {
+    "fort": 6,
+    "ref": 6,
+    "will": 2
+  },
+  "attacks": [
+    {
+      "name": "Hooves (attaque naturelle)",
+      "kind": "melee",
+      "attack_bonus": 8,
+      "damage": [
+        {
+          "formula": "1d4",
+          "types": [
+            "bludgeoning"
+          ]
+        }
+      ],
+      "damage_bonus": 4,
+      "crit_range": 20,
+      "crit_mult": 2,
+      "reach_ft": 5,
+      "count": 2
+    },
+    {
+      "name": "Bite (attaque naturelle)",
+      "kind": "melee",
+      "attack_bonus": 3,
+      "damage": [
+        {
+          "formula": "1d3",
+          "types": [
+            "piercing"
+          ]
+        }
+      ],
+      "damage_bonus": 2,
+      "crit_range": 20,
+      "crit_mult": 2,
+      "reach_ft": 5,
+      "count": 1
+    }
+  ],
+  "source": "fiches_personnages/jeanne_sheet.json"
+}