feat(gameplay): enforce core SRD d20 rules

Co-authored-by: multica-agent <github@multica.ai>

apps/web/pages/campaign/[id].vue

@@ -74,7 +74,7 @@ const timeline = computed(() => {
     })),
     ...payload.value.diceRolls.map(roll => ({
       id: `roll-${roll.id}`, type: 'roll', at: roll.created_at ?? '', label: 'SERVER ROLL',
-      meta: roll.success === null || roll.success === undefined ? roll.check_kind : roll.success ? 'SUCCESS' : 'FAILED',
+      meta: rollMeta(roll),
       body: `${roll.formula} · [${(roll.rolls ?? []).join(', ')}] ${signed(Number(roll.modifier ?? 0))} = ${roll.total}`,
     })),
     ...payload.value.events.map(event => ({
@@ -89,6 +89,29 @@ function signed(value: number) {
   return value >= 0 ? `+ ${value}` : `− ${Math.abs(value)}`
 }
 
+function abilityModifier(score: number) {
+  return Math.floor((Number(score) - 10) / 2)
+}
+
+function abilityLabel(score: number) {
+  const modifier = abilityModifier(score)
+  return modifier >= 0 ? `+${modifier}` : String(modifier)
+}
+
+function rollMeta(roll: Record<string, any>) {
+  if (roll.success === null || roll.success === undefined) return String(roll.check_kind ?? 'ROLL').toUpperCase()
+  const kept = Number(roll.kept?.[0])
+  const outcome = roll.check_kind === 'attack' && kept === 20
+    ? 'CRITICAL HIT'
+    : roll.check_kind === 'attack' && kept === 1
+      ? 'CRITICAL MISS'
+      : roll.success ? 'SUCCESS' : 'FAILED'
+  const target = roll.difficulty === null || roll.difficulty === undefined
+    ? ''
+    : ` · ${roll.check_kind === 'attack' ? 'AC' : 'DC'} ${roll.difficulty}`
+  return `${outcome}${target}`
+}
+
 function initials(name: string) {
   return name.split(/\s+/).map(part => part[0]).join('').slice(0, 2).toUpperCase()
 }
@@ -274,7 +297,7 @@ onBeforeUnmount(() => {
           <textarea v-model="characterForm.concept" required maxlength="600" placeholder="Concept, role, personality" />
           <button type="button" class="ai-draft" :disabled="suggestingCharacter || mutating" @click="suggestCharacter">{{ suggestingCharacter ? 'COAUTHOR IS DRAFTING…' : '✦ DRAFT WITH AI' }}</button>
           <div class="ability-editor"><label v-for="key in (['str','dex','con','int','wis','cha'] as AbilityKey[])" :key="key"><span>{{ key }}</span><input v-model.number="characterForm.abilities[key]" type="number" min="1" max="30"></label></div>
-          <div class="stat-editor"><label>HP <input v-model.number="characterForm.hp" type="number" min="1" :max="characterForm.maxHp"></label><label>MAX <input v-model.number="characterForm.maxHp" type="number" min="1"></label><label>DEF <input v-model.number="characterForm.defense" type="number" min="1" max="40"></label></div>
+          <div class="stat-editor"><label>HP <input v-model.number="characterForm.hp" type="number" min="1" :max="characterForm.maxHp"></label><label>MAX <input v-model.number="characterForm.maxHp" type="number" min="1"></label><label>AC <input v-model.number="characterForm.defense" type="number" min="1" max="40"></label></div>
           <textarea v-model="inventoryText" maxlength="800" placeholder="Starting items, one per line" />
           <details class="persona-editor"><summary>VOICE & PERSONALITY</summary><input v-model="characterForm.persona.voice" maxlength="240" placeholder="Voice"><input v-model="characterForm.persona.motivation" maxlength="300" placeholder="Motivation"><input v-model="characterForm.persona.flaw" maxlength="300" placeholder="Flaw"><input v-model="characterForm.persona.bond" maxlength="300" placeholder="Bond"></details>
           <button class="acid-button" :disabled="mutating">{{ mutating ? 'CREATING…' : 'ADD TO PARTY' }}</button>
@@ -285,8 +308,8 @@ onBeforeUnmount(() => {
         </article>
         <section v-if="myCharacter" class="sheet">
           <small>YOUR CHARACTER</small><h2>{{ myCharacter.name }}</h2><p>{{ myCharacter.concept }}</p>
-          <div class="vitals"><span><b>{{ myCharacter.hp }}</b>/{{ myCharacter.max_hp }} HP</span><span><b>{{ myCharacter.defense }}</b> DEF</span></div>
-          <div class="abilities"><span v-for="(score,key) in myCharacter.abilities" :key="key"><small>{{ key }}</small><b>{{ score }}</b></span></div>
+          <div class="vitals"><span><b>{{ myCharacter.hp }}</b>/{{ myCharacter.max_hp }} HP</span><span><b>{{ myCharacter.defense }}</b> AC</span></div>
+          <div class="abilities"><span v-for="(score,key) in myCharacter.abilities" :key="key"><small>{{ key }} {{ abilityLabel(Number(score)) }}</small><b>{{ score }}</b></span></div>
         </section>
       </aside>
 
@@ -320,7 +343,7 @@ onBeforeUnmount(() => {
         <section class="ai-order"><small>AI TURN ORDER</small><p v-if="!payload.characters.some(character=>character.controller!=='human')">No AI heroes in this party.</p><div v-for="(character,index) in payload.characters.filter(character=>character.controller!=='human')" :key="character.id"><b>{{ String(index+1).padStart(2,'0') }}</b><span>{{ character.name }}<small>{{ character.controller === 'delegated' ? 'Temporary stand-in' : 'Acts after all humans' }}</small></span></div></section>
         <button v-if="isOwner && currentRound?.status==='open'" class="force-button" :disabled="mutating" @click="forceRound">CONTINUE WITHOUT WAITING <span>↗</span></button>
         <button v-if="isOwner && currentRound?.status==='failed'" class="force-button" :disabled="mutating" @click="retryFailedRound">RETRY FAILED ROUND <span>↗</span></button>
-        <div class="mechanics-note"><i /> Dice, HP and mechanical state are resolved by the server and recorded in the campaign log.</div>
+        <div class="mechanics-note"><i /> D20 tests, AC, HP and mechanical state are resolved by the server and recorded in the campaign log.</div>
       </aside>
     </div>
   </AppShell>