feat(03-01): add Module SDK package and Prisma module registry schema

- Create @tessera/module-sdk with TesseraModule, ModuleRoute, ModuleManifest, ModuleCategory types
- Add Module and TenantModuleActivation Prisma models with tenant-scoped unique constraint
- Apply migration add-module-registry to PostgreSQL
- Framework-agnostic ComponentType for lazy-loaded module UIs

packages/module-sdk/src/index.ts

@@ -0,0 +1,14 @@
+/**
+ * @tessera/module-sdk
+ *
+ * Public API for the Tessera module system.
+ * All module implementations should import types from this package.
+ */
+export type {
+  ComponentType,
+  ModuleCategory,
+  HttpMethod,
+  ModuleRoute,
+  TesseraModule,
+  ModuleManifest,
+} from './types';