Add search and scoping filters to saved view MCP tool

What does this MR do and why?

Adds support for search and scoping filters in GetSavedViewWorkItemsTool, covering the second iteration of filter support for the saved view MCP tool. These filters are critical because silently ignoring search or fullPath returns a much broader result set than the user expects.

This MR targets the !227911 (merged) branch (orchestrator service).

Newly supported filters

Filter	GraphQL Variable	Type	Description
search	$search	String	Free-text search across work items
in	$in	[IssuableSearchableField!]	Scope search to title, description, or both
hierarchyFilters	$hierarchyFilters	HierarchyFilterInput	Parent scoping with parentIds, parentWildcardId, includeDescendantWorkItems
fullPath	Overrides $fullPath	ID	Scopes results to a sub-group or project within the namespace

Technical details

search and in: Straightforward pass-through mappings added to the filter_mapping hash and the GraphQL query variables/arguments.

hierarchyFilters: Pass-through of the HierarchyFilterInput object. The saved view stores hierarchy filters as an object with parentIds (array of work item GIDs), parentWildcardId, and includeDescendantWorkItems.

fullPath: This filter is special. Unlike other filters that are arguments to the workItems(...) field, fullPath changes which namespace is queried at the top level (namespace(fullPath: ...)). When a saved view has a fullPath filter (e.g., user scoped the view to a sub-group), the tool overrides the fullPath variable before building the query. This is handled separately from the filter_mapping to avoid it being passed as a workItems argument.

Changes

• get_saved_view_work_items_tool.rb: Added search, in, hierarchyFilters to the GraphQL query and filter_mapping. Added special handling for fullPath to override the namespace scope.
• get_saved_view_work_items_tool_spec.rb: Added unit test contexts for search/in, hierarchyFilters, fullPath override, and updated unsupported filters test (removed search since it's now supported).
• graphql_get_saved_view_work_items_service_spec.rb: Added integration tests for search/in filters (verifies search variables are passed and matching work items are returned), hierarchyFilters (verifies parentIds are passed as GIDs and child work items are returned), and fullPath scoping to both subgroups and projects (verifies the namespace fullPath is overridden and no unsupported filter warnings are emitted).

How to set up and validate locally

Test using MCP inspector with a saved view that has search or group scoping filters applied.

References

• Part of #592440
• Depends on !227911 (merged)
• Iteration 2 of the filter coverage plan

MR acceptance checklist

Evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.