feat: 完成 B 群組 — 資料層與核心領域模型

- 導入 Prisma 7.9.1 + SQLite（better-sqlite3 driver adapter），prisma.config.ts 管理連線設定
- 完整資料模型：User／Work／Character／CharacterAlias／EpisodicMemory／SemanticMemory／
  ProceduralRule／EmotionState／Relationship／SentimentLedgerEntry
- packages/db：Prisma Client 存取層（ESM，因 Prisma 7 產出的 generated client 僅支援 ESM）
- apps/api 隨之改為 ESM 以相容 packages/db
- packages/shared：新增角色／記憶／情緒／關係共用型別，api 與 web 皆從此匯入
- prisma/seed.ts：建立測試使用者與元氣型測試角色，含完整關係帳本與記憶種子資料
- apps/api：新增 GET /characters
- scripts/smoke/B.mjs：驗證資料表齊全、API 讀出種子角色、關係與記憶可寫入讀出
- 保留 Prisma 官方隨 CLI 附的 agent skill 文件（.agents/skills 等），供後續群組查閱

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

.agents/skills/prisma-database-setup/references/prisma-client-setup.md

@@ -0,0 +1,47 @@
+# Prisma Client Setup
+
+Generate and instantiate Prisma Client for Prisma's standard SQL provider workflow. For MongoDB, follow the provider-specific notes in `references/mongodb.md` instead of copying the SQL adapter example below.
+
+## 1. Install dependencies
+
+```bash
+npm install prisma --save-dev
+npm install @prisma/client
+```
+
+## 2. Add generator block
+
+In `prisma/schema.prisma`:
+
+```prisma
+generator client {
+  provider = "prisma-client"
+  output   = "../generated"
+}
+```
+
+`prisma-client` requires an explicit `output` path and does not generate into `node_modules` by default.
+
+## 3. Generate Prisma Client
+
+```bash
+npx prisma generate
+```
+
+Re-run `prisma generate` after every schema change to keep the client in sync.
+
+## 4. Instantiate Prisma Client
+
+```typescript
+import { PrismaClient } from '../generated/client'
+import { PrismaPg } from '@prisma/adapter-pg'
+
+const adapter = new PrismaPg({ connectionString: process.env.DATABASE_URL })
+const prisma = new PrismaClient({ adapter })
+```
+
+If you change the generator `output`, update the import path to match. For the SQL provider workflow, replace `PrismaPg` with the adapter for your database.
+
+## 5. Use a single instance
+
+Each `PrismaClient` instance creates a connection pool. Reuse a single instance per app process to avoid exhausting database connections.