chore: isolate frontend and backend via npm workspaces and @mmapp/contracts

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/modules/events/repository/events-repository.ts

@@ -1,7 +1,7 @@
 import { and, desc, eq, gte, lte } from "drizzle-orm"
 import { db } from "../../../db/index.js"
 import { events } from "../../../db/schema.js"
-import type { EventItem, EventLevel, EventSourceModule } from "../../../../../packages/contracts/dist/events.js"
+import type { EventItem, EventLevel, EventSourceModule } from "@mmapp/contracts/events"
 
 export type EventInsertInput = {
   id: string

backend/src/modules/events/service/events-service.ts

@@ -5,7 +5,7 @@ import {
   type AppendEventBody,
   type EventItem,
   type ListEventsQuery,
-} from "../../../../../packages/contracts/dist/events.js"
+} from "@mmapp/contracts/events"
 import { insertEventsBatch, listEvents, type EventInsertInput } from "../repository/events-repository.js"
 
 function normalizeEventInput(input: AppendEventBody): EventInsertInput {