refactor(db): 统一数据库 schema — 软删除、命名规范、约束标准化

- 全表新增 deleted_at 列，统一软删除替代硬删除+archived_at
- models.model_id 重命名为 external_id，消除语义混淆
- conversations.model_id 改为可空（模型为建议而非绑定）
- messages 新增 updated_at，移除 CASCADE 改为 DAO 层级联
- 移除 DB 层 UNIQUE 约束，改为应用层检查（配合软删除）
- 新增 helpers.ts（baseColumns + 构造层防御）、ESLint 规则、契约测试
- 迁移 0004 补全 CHECK 约束（providers.type/materials.status/messages.role）
- DAO 层全面重写：级联软删除、应用层唯一、provider 删除保护
- 路由/前端/测试全量适配 externalId 重命名及类型变更

tests/server/db/models.test.ts

@@ -41,17 +41,18 @@ describe("模型数据访问层", () => {
         db,
         {
           capabilities: ["text", "reasoning"],
-          modelId: "gpt-4o",
+          externalId: "gpt-4o",
           name: "GPT-4o",
           providerId,
         },
         createNoopLogger(),
       );
       expect("error" in result).toBe(false);
-      const model = (result as { model: { capabilities: string[]; modelId: string; name: string; providerId: string } })
-        .model;
+      const model = (
+        result as { model: { capabilities: string[]; externalId: string; name: string; providerId: string } }
+      ).model;
       expect(model.name).toBe("GPT-4o");
-      expect(model.modelId).toBe("gpt-4o");
+      expect(model.externalId).toBe("gpt-4o");
       expect(model.providerId).toBe(providerId);
       expect(model.capabilities).toEqual(["text", "reasoning"]);
     });
@@ -63,7 +64,7 @@ describe("模型数据访问层", () => {
         db,
         {
           capabilities: ["text"],
-          modelId: "test",
+          externalId: "test",
           name: "Test",
           providerId: "nonexistent",
         },
@@ -77,10 +78,10 @@ describe("模型数据访问层", () => {
   test("同一供应商下模型 ID 唯一", () => {
     withDb((db) => {
       const providerId = seedProvider(db);
-      createModel(db, { capabilities: ["text"], modelId: "gpt-4o", name: "Model1", providerId }, createNoopLogger());
+      createModel(db, { capabilities: ["text"], externalId: "gpt-4o", name: "Model1", providerId }, createNoopLogger());
       const result = createModel(
         db,
-        { capabilities: ["text"], modelId: "gpt-4o", name: "Model2", providerId },
+        { capabilities: ["text"], externalId: "gpt-4o", name: "Model2", providerId },
         createNoopLogger(),
       );
       expect("error" in result).toBe(true);
@@ -94,12 +95,12 @@ describe("模型数据访问层", () => {
       const p2 = seedProvider(db, "P2");
       const r1 = createModel(
         db,
-        { capabilities: ["text"], modelId: "same-id", name: "M1", providerId: p1 },
+        { capabilities: ["text"], externalId: "same-id", name: "M1", providerId: p1 },
         createNoopLogger(),
       );
       const r2 = createModel(
         db,
-        { capabilities: ["text"], modelId: "same-id", name: "M2", providerId: p2 },
+        { capabilities: ["text"], externalId: "same-id", name: "M2", providerId: p2 },
         createNoopLogger(),
       );
       expect("error" in r1).toBe(false);
@@ -112,7 +113,7 @@ describe("模型数据访问层", () => {
       const providerId = seedProvider(db);
       const result = createModel(
         db,
-        { capabilities: [], modelId: "test", name: "Test", providerId },
+        { capabilities: [], externalId: "test", name: "Test", providerId },
         createNoopLogger(),
       );
       expect("error" in result).toBe(true);
@@ -124,9 +125,9 @@ describe("模型数据访问层", () => {
     withDb((db) => {
       const p1 = seedProvider(db, "P1");
       const p2 = seedProvider(db, "P2");
-      createModel(db, { capabilities: ["text"], modelId: "m1", name: "Alpha", providerId: p1 }, createNoopLogger());
-      createModel(db, { capabilities: ["text"], modelId: "m2", name: "Beta", providerId: p1 }, createNoopLogger());
-      createModel(db, { capabilities: ["text"], modelId: "m3", name: "Gamma", providerId: p2 }, createNoopLogger());
+      createModel(db, { capabilities: ["text"], externalId: "m1", name: "Alpha", providerId: p1 }, createNoopLogger());
+      createModel(db, { capabilities: ["text"], externalId: "m2", name: "Beta", providerId: p1 }, createNoopLogger());
+      createModel(db, { capabilities: ["text"], externalId: "m3", name: "Gamma", providerId: p2 }, createNoopLogger());
 
       const all = listModels(db, { page: 1, pageSize: 20 });
       expect(all.total).toBe(3);
@@ -144,7 +145,7 @@ describe("模型数据访问层", () => {
       const providerId = seedProvider(db);
       const created = createModel(
         db,
-        { capabilities: ["text"], modelId: "gpt-4o", name: "GPT-4o", providerId },
+        { capabilities: ["text"], externalId: "gpt-4o", name: "GPT-4o", providerId },
         createNoopLogger(),
       );
       const id = (created as { model: { id: string } }).model.id;
@@ -168,7 +169,7 @@ describe("模型数据访问层", () => {
       const providerId = seedProvider(db);
       const created = createModel(
         db,
-        { capabilities: ["text"], modelId: "gpt-4o", name: "原名", providerId },
+        { capabilities: ["text"], externalId: "gpt-4o", name: "原名", providerId },
         createNoopLogger(),
       );
       const id = (created as { model: { id: string } }).model.id;
@@ -186,7 +187,7 @@ describe("模型数据访问层", () => {
       const providerId = seedProvider(db);
       const created = createModel(
         db,
-        { capabilities: ["text"], modelId: "gpt-4o", name: "删除测试", providerId },
+        { capabilities: ["text"], externalId: "gpt-4o", name: "删除测试", providerId },
         createNoopLogger(),
       );
       const id = (created as { model: { id: string } }).model.id;
@@ -203,9 +204,9 @@ describe("模型数据访问层", () => {
     withDb((db) => {
       const p1 = seedProvider(db, "P1");
       const p2 = seedProvider(db, "P2");
-      createModel(db, { capabilities: ["text"], modelId: "m1", name: "M1", providerId: p1 }, createNoopLogger());
-      createModel(db, { capabilities: ["text"], modelId: "m2", name: "M2", providerId: p1 }, createNoopLogger());
-      createModel(db, { capabilities: ["text"], modelId: "m3", name: "M3", providerId: p2 }, createNoopLogger());
+      createModel(db, { capabilities: ["text"], externalId: "m1", name: "M1", providerId: p1 }, createNoopLogger());
+      createModel(db, { capabilities: ["text"], externalId: "m2", name: "M2", providerId: p1 }, createNoopLogger());
+      createModel(db, { capabilities: ["text"], externalId: "m3", name: "M3", providerId: p2 }, createNoopLogger());
 
       expect(getModelsByProviderId(db, p1)).toBe(2);
       expect(getModelsByProviderId(db, p2)).toBe(1);
@@ -220,8 +221,8 @@ describe("模型数据访问层", () => {
         {
           capabilities: ["text"],
           contextLength: 128000,
+          externalId: "gpt-4o",
           maxOutputTokens: 4096,
-          modelId: "gpt-4o",
           name: "GPT-4o",
           providerId,
         },