feat: add event-based transient stat modifiers on social outcomes

Positive outcomes add +1 sociability modifier (100 ticks).
Negative outcomes add -1 sociability and -1 empathy modifiers (100 ticks).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/systems/__tests__/socialSystem.test.ts

@@ -372,6 +372,41 @@ describe('socialSystem', () => {
       expect(stats.temperament).toBeCloseTo(10.02);
     });
 
+    it('adds positive sociability modifier on positive outcome', () => {
+      const world = new World();
+      const a = createNPC(world, 5, 5);
+      const b = createNPC(world, 8, 5);
+      addStats(world, a);
+      addStats(world, b);
+      const sa = world.getComponent<SocialState>(a, 'socialState')!;
+      const sb = world.getComponent<SocialState>(b, 'socialState')!;
+      sa.phase = 'emoting'; sa.partnerId = b; sa.phaseTimer = 1; sa.outcome = 'positive';
+      sb.phase = 'emoting'; sb.partnerId = a; sb.phaseTimer = 1; sb.outcome = 'positive';
+      socialSystem(world);
+      const mods = world.getComponent<StatModifiers>(a, 'statModifiers')!;
+      const socMod = mods.modifiers.find(m => m.stat === 'sociability' && m.remaining === 100);
+      expect(socMod).toBeDefined();
+      expect(socMod!.value).toBe(1);
+    });
+
+    it('adds negative sociability and empathy modifiers on negative outcome', () => {
+      const world = new World();
+      const a = createNPC(world, 5, 5);
+      const b = createNPC(world, 8, 5);
+      addStats(world, a);
+      addStats(world, b);
+      const sa = world.getComponent<SocialState>(a, 'socialState')!;
+      const sb = world.getComponent<SocialState>(b, 'socialState')!;
+      sa.phase = 'emoting'; sa.partnerId = b; sa.phaseTimer = 1; sa.outcome = 'negative';
+      sb.phase = 'emoting'; sb.partnerId = a; sb.phaseTimer = 1; sb.outcome = 'negative';
+      socialSystem(world);
+      const mods = world.getComponent<StatModifiers>(a, 'statModifiers')!;
+      const socMod = mods.modifiers.find(m => m.stat === 'sociability' && m.remaining === 100);
+      const empMod = mods.modifiers.find(m => m.stat === 'empathy' && m.remaining === 100);
+      expect(socMod?.value).toBe(-1);
+      expect(empMod?.value).toBe(-1);
+    });
+
     it('high empathy biases positive outcome', () => {
       const world = new World();
       let positiveCount = 0;

server/src/systems/socialSystem.ts

@@ -3,7 +3,7 @@ import {
   SOCIAL_GLOBAL_COOLDOWN, SOCIAL_PAIR_COOLDOWN,
   HUNGER_THRESHOLD, ENERGY_THRESHOLD, Direction,
   type SocialState, type Position, type Movement, type NPCBrain, type Needs, type EntityId,
-  type Stats,
+  type Stats, type StatModifiers,
 } from '@dflike/shared';
 import type { World } from '../ecs/World.js';
 import { getEffectiveStat } from './statHelpers.js';
@@ -128,6 +128,26 @@ export function socialSystem(world: World): void {
           }
         }
 
+        // Event-based transient modifiers
+        const modsA = world.getComponent<StatModifiers>(e, 'statModifiers');
+        if (modsA) {
+          if (social.outcome === 'positive') {
+            modsA.modifiers.push({ stat: 'sociability', value: 1, remaining: 100 });
+          } else {
+            modsA.modifiers.push({ stat: 'sociability', value: -1, remaining: 100 });
+            modsA.modifiers.push({ stat: 'empathy', value: -1, remaining: 100 });
+          }
+        }
+        const modsB = world.getComponent<StatModifiers>(partnerId!, 'statModifiers');
+        if (modsB) {
+          if (partnerSocial.outcome === 'positive') {
+            modsB.modifiers.push({ stat: 'sociability', value: 1, remaining: 100 });
+          } else {
+            modsB.modifiers.push({ stat: 'sociability', value: -1, remaining: 100 });
+            modsB.modifiers.push({ stat: 'empathy', value: -1, remaining: 100 });
+          }
+        }
+
         social.phase = 'none';
         social.partnerId = null;
         social.phaseTimer = 0;