Improve role assignment UX with bulk member selection and batch add/remove

[DVidal1205]

Context

During an offboarding roles-assignment thread, Carlos called out a UX gap in Forge/Blade role management:

i cant search multiple ppl and select them all to batch remove or add roles

The immediate use case was taking a KH roster Development bucket list and excluding several people, then needing to add/remove roles for multiple remaining members. The current flow appears to require searching/selecting people one at a time, which makes offboarding/onboarding role cleanup slow and error-prone.

Problem

Admins/officers need a way to search for multiple people and apply role assignment changes in bulk.

Current pain points:

• Cannot search/select multiple people in one pass.
• Cannot batch add roles to selected people.
• Cannot batch remove roles from selected people.
• Large offboarding/onboarding updates become repetitive and easy to mess up.

Desired UX

Support a bulk role assignment workflow for admins, such as:

1. Search and select multiple members before applying changes.
2. Review the selected members before submitting.
3. Choose one or more roles to add and/or remove.
4. Confirm the batch operation with a clear summary.
5. Show success/failure feedback per member if some operations fail.

Acceptance Criteria

• Admin can select multiple people from member search results.
• Admin can add at least one role to all selected people in a single action.
• Admin can remove at least one role from all selected people in a single action.
• UI includes a review/confirmation step summarizing selected members and role changes.
• Partial failures are surfaced clearly instead of silently failing the whole batch.
• Existing single-person role assignment behavior still works.

Notes

Source request came from the directors/offboarding discussion. This is a UX/product ticket; implementation details can be scoped after reviewing the current role management surfaces in Forge/Blade.