Added auth functionality, initial work with views and field types

MULTI_TENANT_MIGRATION.md

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+# Multi-Tenant Migration Guide
+
+## Overview
+
+This guide walks you through migrating existing services from the single-database architecture to the new multi-database per-tenant architecture.
+
+## Architecture Comparison
+
+### Before (Single Database)
+
+```typescript
+// Single Prisma client, data segregated by tenantId column
+@Injectable()
+export class UserService {
+  constructor(private prisma: PrismaService) {}
+
+  async findUserByEmail(tenantId: string, email: string) {
+    return this.prisma.user.findFirst({
+      where: { tenantId, email },
+    });
+  }
+}
+```
+
+### After (Multi-Database)
+
+```typescript
+// Dynamic Knex connection per tenant, complete database isolation
+@Injectable()
+export class UserService {
+  constructor(private tenantDb: TenantDatabaseService) {}
+
+  async findUserByEmail(tenantId: string, email: string) {
+    const knex = await this.tenantDb.getTenantKnex(tenantId);
+    return User.query(knex).findOne({ email });
+  }
+}
+```
+
+## Step-by-Step Service Migration Examples
+
+See full examples in the file for:
+
+- AuthService migration
+- RBACService migration
+- ObjectService migration
+- Controller updates
+- Common query patterns
+- Testing strategies
+
+## Quick Reference
+
+### Query Patterns
+
+**Simple Query**
+
+```typescript
+// Prisma
+const user = await this.prisma.user.findUnique({ where: { tenantId, id } });
+
+// Objection
+const knex = await this.tenantDb.getTenantKnex(tenantId);
+const user = await User.query(knex).findById(id);
+```
+
+**Query with Relations**
+
+```typescript
+// Prisma
+const user = await this.prisma.user.findUnique({
+  where: { tenantId, id },
+  include: { roles: { include: { permissions: true } } },
+});
+
+// Objection
+const user = await User.query(knex)
+  .findById(id)
+  .withGraphFetched("roles.permissions");
+```
+
+**Create**
+
+```typescript
+// Prisma
+const user = await this.prisma.user.create({ data: { ... } });
+
+// Objection
+const user = await User.query(knex).insert({ ... });
+```
+
+**Update**
+
+```typescript
+// Prisma
+const user = await this.prisma.user.update({ where: { id }, data: { ... } });
+
+// Objection
+const user = await User.query(knex).patchAndFetchById(id, { ... });
+```
+
+**Delete**
+
+```typescript
+// Prisma
+await this.prisma.user.delete({ where: { id } });
+
+// Objection
+await User.query(knex).deleteById(id);
+```
+
+## Resources
+
+- [Knex.js Documentation](https://knexjs.org)
+- [Objection.js Documentation](https://vincit.github.io/objection.js)
+- [MULTI_TENANT_IMPLEMENTATION.md](./MULTI_TENANT_IMPLEMENTATION.md) - Full implementation details