feat: move admin panel to dedicated /admin-panel GraphQL endpoint (#19852)

## Summary

Splits admin-panel resolvers off the shared `/metadata` GraphQL endpoint
onto a dedicated `/admin-panel` endpoint. The backend plumbing mirrors
the existing `metadata` / `core` pattern (new scope, decorator, module,
factory), and admin types now live in their own
`generated-admin/graphql.ts` on the frontend — dropping 877 lines of
admin noise from `generated-metadata`.

## Why

- **Smaller attack surface on `/metadata`** — every authenticated user
hits that endpoint; admin ops don't belong there.
- **Independent complexity limits and monitoring** per endpoint.
- **Cleaner module boundaries** — admin is a cross-cutting concern that
doesn't match the "shared-schema configuration" meaning of `/metadata`.
- **Deploy / blast-radius isolation** — a broken admin query can't
affect `/metadata`.

Runtime behavior, auth, and authorization are unchanged — this is a
relocation, not a re-permissioning. All existing guards
(`WorkspaceAuthGuard`, `UserAuthGuard`,
`SettingsPermissionGuard(SECURITY)` at class level; `AdminPanelGuard` /
`ServerLevelImpersonateGuard` at method level) remain on
`AdminPanelResolver`.

## What changed

### Backend
- `@AdminResolver()` decorator with scope `'admin'`, naming parallels
`CoreResolver` / `MetadataResolver`.
- `AdminPanelGraphQLApiModule` + `adminPanelModuleFactory` registered at
`/admin-panel`, same Yoga hook set as the metadata factory (Sentry
tracing, error handler, introspection-disabling in prod, complexity
validation).
- Middleware chain on `/admin-panel` is identical to `/metadata`.
- `@nestjs/graphql` patch extended: `resolverSchemaScope?: 'core' |
'metadata' | 'admin'`.
- `AdminPanelResolver` class decorator swapped from
`@MetadataResolver()` to `@AdminResolver()` — no other changes.

### Frontend
- `codegen-admin.cjs` → `src/generated-admin/graphql.ts` (982 lines).
- `codegen-metadata.cjs` excludes admin paths; metadata file shrinks by
877 lines.
- `ApolloAdminProvider` / `useApolloAdminClient` follow the existing
`ApolloCoreProvider` / `useApolloCoreClient` pattern, wired inside
`AppRouterProviders` alongside the core provider.
- 37 admin consumer files migrated: imports switched to
`~/generated-admin/graphql` and `client: useApolloAdminClient()` is
passed to `useQuery` / `useMutation`.
- Three files intentionally kept on `generated-metadata` because they
consume non-admin Documents: `useHandleImpersonate.ts`,
`SettingsAdminApplicationRegistrationDangerZone.tsx`,
`SettingsAdminApplicationRegistrationGeneralToggles.tsx`.

### CI
- `ci-server.yaml` runs all three `graphql:generate` configurations and
diff-checks all three generated dirs.

## Authorization (unchanged, but audited while reviewing)

Every one of the 38 methods on `AdminPanelResolver` has a method-level
guard:
- `AdminPanelGuard` (32 methods) — requires `canAccessFullAdminPanel ===
true`
- `ServerLevelImpersonateGuard` (6 methods: user/workspace lookup + chat
thread views) — requires `canImpersonate === true`

On top of the class-level guards above. No resolver method is accessible
without these flags + `SECURITY` permission in the workspace.

## Test plan

- [ ] Dev server boots; `/graphql`, `/metadata`, `/admin-panel` all
mapped as separate GraphQL routes (confirmed locally during
development).
- [ ] `nx typecheck twenty-server` passes.
- [ ] `nx typecheck twenty-front` passes.
- [ ] `nx lint:diff-with-main twenty-server` and `twenty-front` both
clean.
- [ ] Manual smoke test: log in with a user who has
`canAccessFullAdminPanel=true`, open the admin panel at
`/settings/admin-panel`, verify each tab loads (General, Health, Config
variables, AI, Apps, Workspace details, User details, chat threads).
- [ ] Manual smoke test: log in with a user who has
`canImpersonate=false` and `canAccessFullAdminPanel=false`, hit
`/admin-panel` directly with a raw GraphQL request, confirm permission
error on every operation.
- [ ] Production deploy note: reverse proxy / ingress must route the new
`/admin-panel` path to the Nest server. If the proxy has an explicit
allowlist, infra change required before cutover.

## Follow-ups (out of scope here)

- Consider cutting over the three
`SettingsAdminApplicationRegistration*` components to admin-scope
versions of the app-registration operations so the admin page is fully
on the admin endpoint.
- The `renderGraphiQL` double-assignment in
`admin-panel.module-factory.ts` is copied from
`metadata.module-factory.ts` — worth cleaning up in both.

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

@@ -58,7 +58,7 @@ import { type AiProviderModelConfig } from 'src/engine/metadata-modules/ai/ai-mo
 import { extractConfigVariableName } from 'src/engine/metadata-modules/ai/ai-models/utils/extract-config-variable-name.util';
 import { loadDefaultAiProviders } from 'src/engine/metadata-modules/ai/ai-models/utils/load-default-ai-providers.util';
 import { WorkspaceEntity } from 'src/engine/core-modules/workspace/workspace.entity';
-import { MetadataResolver } from 'src/engine/api/graphql/graphql-config/decorators/metadata-resolver.decorator';
+import { AdminResolver } from 'src/engine/api/graphql/graphql-config/decorators/admin-resolver.decorator';
 import { AdminPanelGuard } from 'src/engine/guards/admin-panel-guard';
 import { ServerLevelImpersonateGuard } from 'src/engine/guards/server-level-impersonate.guard';
 import { SettingsPermissionGuard } from 'src/engine/guards/settings-permission.guard';
@@ -74,7 +74,7 @@ import { SetMaintenanceModeInput } from './dtos/set-maintenance-mode.input';
 import { AuthWorkspace } from 'src/engine/decorators/auth/auth-workspace.decorator';
 
 @UsePipes(ResolverValidationPipe)
-@MetadataResolver()
+@AdminResolver()
 @UseFilters(
   AuthGraphqlApiExceptionFilter,
   PreventNestToAutoLogGraphqlErrorsFilter,