fix: add TenantContextMiddleware to initialize tenant context from X-Tenant-Id header

All services using TenantAwareRepository require AsyncLocalStorage tenant
context to set the correct PostgreSQL search_path. The middleware reads
X-Tenant-Id from request headers and wraps the request with
TenantContextService.run(), using schema naming convention it0_t_{tenantId}.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/shared/database/src/database.module.ts

@@ -1,9 +1,14 @@
-import { DynamicModule, Module } from '@nestjs/common';
+import { DynamicModule, MiddlewareConsumer, Module, NestModule } from '@nestjs/common';
 import { TypeOrmModule } from '@nestjs/typeorm';
 import { ConfigService } from '@nestjs/config';
+import { TenantContextMiddleware } from './tenant-context.middleware';
 
 @Module({})
-export class DatabaseModule {
+export class DatabaseModule implements NestModule {
+  configure(consumer: MiddlewareConsumer) {
+    consumer.apply(TenantContextMiddleware).forRoutes('*');
+  }
+
   static forRoot(): DynamicModule {
     return {
       module: DatabaseModule,

packages/shared/database/src/index.ts

@@ -1,3 +1,4 @@
 export * from './tenant-aware.repository';
 export * from './database.module';
 export * from './tenant-provisioning.service';
+export * from './tenant-context.middleware';

packages/shared/database/src/tenant-context.middleware.ts

@@ -0,0 +1,24 @@
+import { Injectable, NestMiddleware } from '@nestjs/common';
+import { Request, Response, NextFunction } from 'express';
+import { TenantContextService } from '@it0/common';
+import { TenantInfo } from '@it0/common';
+
+@Injectable()
+export class TenantContextMiddleware implements NestMiddleware {
+  use(req: Request, res: Response, next: NextFunction) {
+    const tenantId = req.headers['x-tenant-id'] as string;
+
+    if (!tenantId) {
+      return next();
+    }
+
+    const tenantInfo: TenantInfo = {
+      tenantId,
+      tenantName: tenantId,
+      plan: 'free',
+      schemaName: `it0_t_${tenantId}`,
+    };
+
+    TenantContextService.run(tenantInfo, () => next());
+  }
+}