feat: 完成 C 群組 — 記憶子系統

- WorkingMemoryService：session 對話上下文緩衝，token 溢位時優先裁切最舊的低情緒段落
- JobQueue 抽象層（now/schedule(at)/every(cron)）與 InProcessJobQueue 實作（node-cron），
  R-6 會換成 BullMQ 但呼叫端介面不變
- MemoryConsolidationService：睡眠固化，只有高情緒或重複提及的內容才寫入 EpisodicMemory
- ForgettingSweepService：低情緒且長期未提取的記憶逐次降權、weight 過低後刪除，
  已掛上每小時一次的 JobQueue.every 排程
- KeywordMemoryRetriever：關鍵字＋時間近因＋情緒權重排序，提取命中即更新提取次數／時間
- apps/api 新增 /memory/* 端點作為引擎驗證介面（H 群組會決定併入正式對話管線後的去留）
- scripts/smoke/C.mjs：端到端驗證溢位裁切、只寫工作記憶、固化篩選、檢索排序、
  提取即改寫、schedule(at) 準時觸發、遺忘衰減與刪除

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

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

@@ -0,0 +1,82 @@
+import { Body, Controller, Get, Param, Post, Query } from "@nestjs/common";
+import type { EmotionTag } from "@kokorone/shared";
+import { WorkingMemoryService } from "./working-memory.service.js";
+import { MemoryConsolidationService } from "./memory-consolidation.service.js";
+import { ForgettingSweepService } from "./forgetting-sweep.service.js";
+import { KeywordMemoryRetriever } from "./memory-retriever.service.js";
+import { InProcessJobQueue } from "./in-process-job-queue.service.js";
+
+interface AppendMessageBody {
+  role: "user" | "character";
+  content: string;
+  emotionTag?: EmotionTag;
+  emotionIntensity?: number;
+}
+
+@Controller("memory")
+export class MemoryController {
+  // C-3 排程抽象層驗證用：記錄測試性延遲工作是否已觸發，僅供 smoke test 檢查 schedule(at) 準時性。
+  private readonly scheduledJobFired = new Map<string, boolean>();
+
+  constructor(
+    private readonly workingMemory: WorkingMemoryService,
+    private readonly consolidation: MemoryConsolidationService,
+    private readonly forgettingSweep: ForgettingSweepService,
+    private readonly retriever: KeywordMemoryRetriever,
+    private readonly jobQueue: InProcessJobQueue,
+  ) {}
+
+  @Post(":characterId/sessions/:sessionId/messages")
+  appendMessage(@Param("sessionId") sessionId: string, @Body() body: AppendMessageBody) {
+    this.workingMemory.append(sessionId, {
+      role: body.role,
+      content: body.content,
+      timestamp: new Date(),
+      emotionTag: body.emotionTag,
+      emotionIntensity: body.emotionIntensity,
+    });
+    return { context: this.workingMemory.getContext(sessionId) };
+  }
+
+  @Get(":characterId/sessions/:sessionId/messages")
+  getContext(@Param("sessionId") sessionId: string) {
+    return { context: this.workingMemory.getContext(sessionId) };
+  }
+
+  @Post(":characterId/sessions/:sessionId/consolidate")
+  async consolidate(@Param("characterId") characterId: string, @Param("sessionId") sessionId: string) {
+    await this.consolidation.consolidate(characterId, sessionId);
+    return { ok: true };
+  }
+
+  @Get(":characterId/retrieve")
+  async retrieve(
+    @Param("characterId") characterId: string,
+    @Query("query") query: string,
+    @Query("limit") limit?: string,
+  ) {
+    const results = await this.retriever.retrieve(characterId, query ?? "", limit ? Number(limit) : undefined);
+    return { results };
+  }
+
+  @Post("forgetting-sweep")
+  async runForgettingSweep(@Body() body: { now?: string }) {
+    const now = body?.now ? new Date(body.now) : new Date();
+    return this.forgettingSweep.run(now);
+  }
+
+  @Post("test-scheduled-job")
+  scheduleTestJob(@Body() body: { id: string; delaySeconds: number }) {
+    this.scheduledJobFired.set(body.id, false);
+    const at = new Date(Date.now() + body.delaySeconds * 1000);
+    this.jobQueue.schedule(at, `test-job-${body.id}`, () => {
+      this.scheduledJobFired.set(body.id, true);
+    });
+    return { scheduled: true };
+  }
+
+  @Get("test-scheduled-job/:id")
+  checkTestJob(@Param("id") id: string) {
+    return { fired: this.scheduledJobFired.get(id) ?? false };
+  }
+}