feat!: 拆分 core / server 入口,peer deps 全部 optional

让只用 Shrimp 核心(RPC + 模块声明 + 内存 CRUD)的项目不必装
express / mongoose / bcrypt / jsonwebtoken,显著降低 install 时间。

- src/core.ts:0 重依赖入口(Shrimp / MemoryShrimpCrud / 类型)
- src/server.ts:在 core 之上再导出 ShrimpServer + MongoShrimpCrud
- package.json:加 exports 字段 + peerDependenciesMeta.optional
- Shrimp.ts:bcrypt 改 lazy import,只有走 Password 字段才触发
- MemoryShrimpCrud.populateItems:接 crudRegistry 参数(对齐 Mongo)
- ShrimpTableModule 构造时自动登记 crudRegistry,业务无需手动 wire
- 新增 test/crudRegistry.test.ts 验证自动登记 + relation 自动 populate

BREAKING: import { ShrimpServer } from 'shrimp-server' 不再可用,
请改为 'shrimp-server/server'。

package.json

@@ -1,10 +1,21 @@
 {
     "name": "shrimp-server",
-    "version": "0.1.0",
+    "version": "0.2.0",
     "private": true,
     "description": "Shrimp 框架后端 — 声明式字段驱动的 Node.js 管理后台框架(Express + Mongoose + JWT)",
     "main": "src/index.ts",
     "types": "src/index.ts",
+    "exports": {
+        ".": {
+            "types": "./src/core.ts",
+            "default": "./src/core.ts"
+        },
+        "./server": {
+            "types": "./src/server.ts",
+            "default": "./src/server.ts"
+        },
+        "./package.json": "./package.json"
+    },
     "files": [
         "src",
         "README.md"
@@ -21,6 +32,12 @@
         "jsonwebtoken": "^8 || ^9",
         "bcrypt": "^5 || ^6"
     },
+    "peerDependenciesMeta": {
+        "express": { "optional": true },
+        "mongoose": { "optional": true },
+        "jsonwebtoken": { "optional": true },
+        "bcrypt": { "optional": true }
+    },
     "devDependencies": {
         "@types/express": "^4.17.21",
         "@types/jsonwebtoken": "^9.0.0",