feat(M02-A): 建立多小程序租户配置模型

backend/src/routes/platform-bootstrap.ts

@@ -0,0 +1,55 @@
+import type { FastifyInstance } from 'fastify';
+import { z } from 'zod';
+import {
+  AmbiguousAppTenantError,
+  type PlatformBootstrap
+} from '../tenancy/platform-config-repository.js';
+
+const headerSchema = z.object({
+  'x-wechat-appid': z.string().trim().min(6).max(64),
+  'tenant-id': z.string().regex(/^[1-9]\d{0,19}$/).optional()
+});
+
+export interface PlatformConfigResolver {
+  resolveBootstrap(appId: string, tenantId?: string): Promise<PlatformBootstrap | null>;
+}
+
+export async function registerPlatformBootstrapRoutes(
+  app: FastifyInstance,
+  repository: PlatformConfigResolver
+): Promise<void> {
+  app.get('/app-api/bootstrap', async (request, reply) => {
+    const parsed = headerSchema.safeParse(request.headers);
+    if (!parsed.success) {
+      return reply.status(400).send({
+        code: 'INVALID_APP_CONTEXT',
+        message: 'x-wechat-appid is required and tenant-id must be a positive integer.',
+        traceId: request.traceId
+      });
+    }
+
+    try {
+      const bootstrap = await repository.resolveBootstrap(
+        parsed.data['x-wechat-appid'],
+        parsed.data['tenant-id']
+      );
+      if (!bootstrap) {
+        return reply.status(404).send({
+          code: 'APP_TENANT_NOT_FOUND',
+          message: 'The application and tenant binding is not active.',
+          traceId: request.traceId
+        });
+      }
+      return { code: 0, data: bootstrap, traceId: request.traceId };
+    } catch (error) {
+      if (error instanceof AmbiguousAppTenantError) {
+        return reply.status(409).send({
+          code: 'TENANT_SELECTION_REQUIRED',
+          message: error.message,
+          traceId: request.traceId
+        });
+      }
+      throw error;
+    }
+  });
+}