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/applicationVariable/application-variable.resolver.ts

@@ -1,11 +1,5 @@
 import { UseFilters, UseGuards } from '@nestjs/common';
-import {
-  Args,
-  Mutation,
-  Parent,
-  ResolveField,
-  Resolver,
-} from '@nestjs/graphql';
+import { Args, Mutation, Parent, ResolveField } from '@nestjs/graphql';
 
 import { PermissionFlagType } from 'twenty-shared/constants';
 
@@ -16,6 +10,7 @@ import { ApplicationVariableEntityDTO } from 'src/engine/core-modules/applicatio
 import { UpdateApplicationVariableEntityInput } from 'src/engine/core-modules/applicationVariable/dtos/update-application-variable.input';
 import { WorkspaceEntity } from 'src/engine/core-modules/workspace/workspace.entity';
 import { AuthWorkspace } from 'src/engine/decorators/auth/auth-workspace.decorator';
+import { MetadataResolver } from 'src/engine/api/graphql/graphql-config/decorators/metadata-resolver.decorator';
 import { SettingsPermissionGuard } from 'src/engine/guards/settings-permission.guard';
 import { WorkspaceAuthGuard } from 'src/engine/guards/workspace-auth.guard';
 
@@ -23,7 +18,7 @@ import { WorkspaceAuthGuard } from 'src/engine/guards/workspace-auth.guard';
   WorkspaceAuthGuard,
   SettingsPermissionGuard(PermissionFlagType.APPLICATIONS),
 )
-@Resolver(() => ApplicationVariableEntityDTO)
+@MetadataResolver(() => ApplicationVariableEntityDTO)
 @UseFilters(ApplicationVariableEntityExceptionFilter)
 export class ApplicationVariableEntityResolver {
   constructor(