Prevent leak between /metadata and /graphql GQL schemas (#17845)

## Fix resolver schema leaking between `/metadata` and `/graphql`
endpoints

### Summary
- Patch `@nestjs/graphql` to support a `resolverSchemaScope` option that
filters resolvers at both schema generation and runtime, preventing
cross-endpoint leaking
- Introduce `@CoreResolver()` and `@MetadataResolver()` decorators to
explicitly scope each resolver to its endpoint
- Move most resolvers (auth, billing, workspace, user, etc.) to the
metadata schema where the frontend expects them; only workflow and
timeline calendar/messaging resolvers remain on `/graphql`
- Fix frontend `SSEQuerySubscribeEffect` to use the default (metadata)
Apollo client instead of the core client

### Problem
NestJS GraphQL's module-based resolver discovery traverses transitive
imports, causing resolvers from `/metadata` modules to leak into the
`/graphql` schema and vice versa. This made the schemas unpredictable
and tightly coupled to module import order.

### Approach
- Added `resolverSchemaScope` to `GqlModuleOptions` via a patch on
`@nestjs/graphql`, filtering in both `filterResolvers()` (runtime
binding) and `getAllCtors()` (schema generation)
- Each resolver is explicitly decorated with `@CoreResolver()` or
`@MetadataResolver()`
- Organized decorator, constant, and type files under `graphql-config/`
following project conventions


Core GQL Schema: (see: no more fields!)
<img width="827" height="894" alt="image"
src="https://github.com/user-attachments/assets/668f3f0f-485e-43f0-92be-4345aeccacb6"
/>

Metadata GQL Schema (see no more getTimelineCalendarEventsFromCompany)
<img width="827" height="894" alt="image"
src="https://github.com/user-attachments/assets/443913db-e5fe-4161-b0e7-4a971cc80a71"
/>

packages/twenty-server/src/engine/core-modules/billing/billing.resolver.ts

@@ -1,7 +1,7 @@
 /* @license Enterprise */
 
 import { UseFilters, UseGuards, UsePipes } from '@nestjs/common';
-import { Args, Mutation, Query, Resolver } from '@nestjs/graphql';
+import { Args, Mutation, Query } from '@nestjs/graphql';
 
 import { PermissionFlagType } from 'twenty-shared/constants';
 import { WorkspaceActivationStatus } from 'twenty-shared/workspace';
@@ -46,8 +46,9 @@ import {
 } from 'src/engine/metadata-modules/permissions/permissions.exception';
 import { PermissionsService } from 'src/engine/metadata-modules/permissions/permissions.service';
 import { PermissionsGraphqlApiExceptionFilter } from 'src/engine/metadata-modules/permissions/utils/permissions-graphql-api-exception.filter';
+import { MetadataResolver } from 'src/engine/api/graphql/graphql-config/decorators/metadata-resolver.decorator';
 
-@Resolver()
+@MetadataResolver()
 @UsePipes(ResolverValidationPipe)
 @UseFilters(
   PermissionsGraphqlApiExceptionFilter,