Enhance role-check system with stricter checks (#15392)

## Overview

This PR strengthens our permission system by introducing more granular
role-based access control across the platform.

## Changes

### New Permissions Added
- **Applications** - Control who can install and manage applications
- **Layouts** - Control who can customize page layouts and UI structure
- **AI** - Control access to AI features and agents
- **Upload File** - Separate permission for file uploads
- **Download File** - Separate permission for file downloads (frontend
visibility)

### Security Enhancements
- Implemented whitelist-based validation for workspace field updates
- Added explicit permission guards to core entity resolvers
- Enhanced ESLint rule to enforce permission checks on all mutations
- Created `CustomPermissionGuard` and `NoPermissionGuard` for better
code documentation

### Affected Components
- Core entity resolvers: webhooks, files, domains, applications,
layouts, postgres credentials
- Workspace update mutations now use whitelist validation
- Settings UI updated with new permission controls

### Developer Experience
- ESLint now catches missing permission guards during development
- Explicit guard markers make permission requirements clear in code
review
- Comprehensive test coverage for new permission logic

## Testing
- ✅ All TypeScript type checks pass
- ✅ ESLint validation passes
- ✅ New permission guards properly enforced
- ✅ Frontend UI displays new permissions correctly

## Migration Notes
Existing workspaces will need to assign the new permissions to roles as
needed. By default, all new permissions are set to `false` for non-admin
roles.

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

@@ -10,6 +10,7 @@ import {
 import { ResolverValidationPipe } from 'src/engine/core-modules/graphql/pipes/resolver-validation.pipe';
 import { ImpersonationService } from 'src/engine/core-modules/impersonation/services/impersonation.service';
 import { AuthUserWorkspaceId } from 'src/engine/decorators/auth/auth-user-workspace-id.decorator';
+import { CustomPermissionGuard } from 'src/engine/guards/custom-permission.guard';
 import { ImpersonatePermissionGuard } from 'src/engine/guards/impersonate-permission.guard';
 import { NoImpersonationGuard } from 'src/engine/guards/no-impersonation.guard';
 import { UserAuthGuard } from 'src/engine/guards/user-auth.guard';
@@ -25,6 +26,7 @@ export class ImpersonationResolver {
     UserAuthGuard,
     NoImpersonationGuard,
     ImpersonatePermissionGuard,
+    CustomPermissionGuard,
   )
   @Mutation(() => ImpersonateOutput)
   async impersonate(