feat: 完成 E 群組 — 關係子系統

- RelationshipService：E-1 未知對象自動建檔（禮貌+防備＝intimacy/trust=0）、
  E-3 親密度五階分層＋跨階事件（@nestjs/event-emitter，StageChangeLogService 獨立訂閱）、
  E-4 久未互動時親密度半衰期衰減並標記「久未見」
- SentimentLedgerService：E-2 關係帳本，負向事件套用放大係數，驗證同等級正負事件淨值為負
- IntentInterpreterService：E-6 依親密度將同一句模稜兩可的話解讀為玩笑或冒犯
- KeywordMemoryRetriever（C-6）擴充 E-5：新增 relatedUserId 加權，retrieve() 簽名改為接受 options 物件
- schema 新增 EpisodicMemory.relatedUserId，並補上所有子表對父表的 onDelete: Cascade/SetNull
  （E-2 測試時發現先前 B 群組遺漏這些規則會導致刪除關係時外鍵違反）
- apps/api 新增 /relationships/* 端點作為引擎驗證介面
- scripts/smoke/E.mjs：涵蓋 E-1~E-6 全部驗收情境

npm run restart && npm run smoke -- E 皆通過（E-V），A/B/C/D 群組冒煙測試無回歸。

本次另排除一個本機環境限定的 Prisma CLI 網路 checkpoint 卡住問題，並從一次部分套用的
migration 中手動恢復資料庫一致性（過程記錄於 todo.md 實作記錄，供後續群組參考）。

apps/api/src/memory/memory-retriever.service.ts

@@ -2,14 +2,21 @@ import { Injectable } from "@nestjs/common";
 import type { EpisodicMemory } from "@kokorone/shared";
 import { PrismaService } from "../prisma/prisma.service.js";
 
+export interface RetrieveOptions {
+  limit?: number;
+  // E-5 關係加權檢索接點：與此使用者相關的記憶會被加權排到前面。
+  relatedUserId?: string;
+}
+
 export interface MemoryRetriever {
-  retrieve(characterId: string, query: string, limit?: number): Promise<EpisodicMemory[]>;
+  retrieve(characterId: string, query: string, options?: RetrieveOptions): Promise<EpisodicMemory[]>;
 }
 
 const WEIGHTS = {
-  keyword: 0.5,
-  recency: 0.3,
-  emotion: 0.2,
+  keyword: 0.4,
+  recency: 0.25,
+  emotion: 0.15,
+  relationship: 0.2,
 };
 
 const DEFAULT_LIMIT = 5;
@@ -28,7 +35,8 @@ function keywordRelevance(content: string, keywords: string[]): number {
 export class KeywordMemoryRetriever implements MemoryRetriever {
   constructor(private readonly prisma: PrismaService) {}
 
-  async retrieve(characterId: string, query: string, limit = DEFAULT_LIMIT): Promise<EpisodicMemory[]> {
+  async retrieve(characterId: string, query: string, options: RetrieveOptions = {}): Promise<EpisodicMemory[]> {
+    const limit = options.limit ?? DEFAULT_LIMIT;
     const rows = await this.prisma.client.episodicMemory.findMany({ where: { characterId } });
     const now = Date.now();
     const keywords = query.split(/\s+/).filter(Boolean);
@@ -38,8 +46,12 @@ export class KeywordMemoryRetriever implements MemoryRetriever {
       const daysSince = (now - row.occurredAt.getTime()) / (1000 * 60 * 60 * 24);
       const recencyScore = 1 / (1 + Math.max(0, daysSince));
       const emotionScore = row.emotionIntensity;
+      const relationshipScore = options.relatedUserId && row.relatedUserId === options.relatedUserId ? 1 : 0;
       const score =
-        keywordScore * WEIGHTS.keyword + recencyScore * WEIGHTS.recency + emotionScore * WEIGHTS.emotion;
+        keywordScore * WEIGHTS.keyword +
+        recencyScore * WEIGHTS.recency +
+        emotionScore * WEIGHTS.emotion +
+        relationshipScore * WEIGHTS.relationship;
       return { row, score };
     });
 

apps/api/src/memory/memory.controller.ts

@@ -54,8 +54,12 @@ export class MemoryController {
     @Param("characterId") characterId: string,
     @Query("query") query: string,
     @Query("limit") limit?: string,
+    @Query("relatedUserId") relatedUserId?: string,
   ) {
-    const results = await this.retriever.retrieve(characterId, query ?? "", limit ? Number(limit) : undefined);
+    const results = await this.retriever.retrieve(characterId, query ?? "", {
+      limit: limit ? Number(limit) : undefined,
+      relatedUserId,
+    });
     return { results };
   }