[BE] Return custom work item types through the types provider in GraphQL

Followup based on this discussion

Thank you for working on this @daniyalAD 🙇 I checkout this out in my gdk and I could finally see the new CWIT is created That's so exciting

I just wanted to know that how if the namespaceWorkItemTypes query should return the created WIT ? Because I could not see it when I fetched it again 🤔 If not , which backend issue would target it ?

Summary

Update the TypesFramework::Provider to return custom work item types in the namespaceWorkItemTypes GraphQL query, similar to how system defined types are handled.

Context

• Discussion originated from: !223304 (merged) (comment)
• Related MR for system defined types: !223538 (merged)
• Related issue for creating custom types: #581937 (closed)
• Parent epic: &19883

Currently, when a custom work item type (CWIT) is created via the workItemTypeCreate mutation, it is not returned by the namespaceWorkItemTypes query. This is because the TypesFramework::Provider only returns system-defined types.

Technical Details

The following files are relevant for incorporating custom work item types in graphQL:

File	Purpose
app/graphql/resolvers/work_items/types_resolver.rb	GraphQL Resolver - Uses WorkItems::TypesFinder to fetch types
app/finders/work_items/types_finder.rb	Finder - Uses TypesFramework::Provider to get types
app/models/work_items/types_framework/provider.rb	Provider (main logic) - all_ordered_by_name method is the entry point for fetching all work item types
app/models/work_items/types_filter.rb	Filter - allowed_types method filters which types are available

Implementation Approach

The Provider class at app/models/work_items/types_framework/provider.rb is the single source of truth. It currently returns system-defined types but needs to be updated to also include custom types from WorkItems::TypesFramework::Custom::Type.

Follow a similar approach to !223538 (merged) (incorporating system defined types into the types provider) to add custom work item types.

Acceptance Criteria

• Custom work item types created via workItemTypeCreate mutation are returned by namespaceWorkItemTypes query
• Custom types are properly filtered based on namespace context
• Existing system-defined types behavior is preserved