Add a Group Management component for authorization

[d-ryan-ashcraft]

Summary

Introduce a new, reusable UI component — codifyiq_group_manager — that lets any app manage authorization groups and assign them to users in a consistent, polished way. Today each project that needs "who belongs to which group" reinvents the screens; this gives us one drop-in, Material Design 3 surface to reuse everywhere.

Motivation

Most of our apps eventually need some form of access control. The common, lightweight shape is simply: a user belongs to one or more groups, and the app derives permissions from that membership. We keep rebuilding that UI ad hoc, with inconsistent look-and-feel and varying quality. A shared component removes the duplicated effort and gives users a familiar experience across products.

Scope

• Manage the group catalog — create, edit, and delete groups, with a clear, searchable list that holds up when the catalog grows.
• Assign groups to a user — pick one or more groups for a given person quickly, with search for when there are many groups.
• Presentation only — the component owns the UX and in-memory state; each app wires it to its own backend/persistence. It does not perform real authorization.

Non-goals (keep it simple, by design)

• No nested/hierarchical groups.
• No separate "roles" concept distinct from groups.
• No opinion about how permissions are stored or enforced server-side.

Intent / quality bar

• Consistent Material Design 3 throughout, using classic, well-understood UI patterns.
• Theme-aware — colors and styling follow each host app's theme automatically (including light/dark), so it looks native wherever it's dropped in.
• Adaptive — works well from mobile widths to large desktop windows, with sensible layout and comfortable content width on big screens.
• Drop-in and composable — usable as a complete screen for the common case, or as smaller building blocks for custom flows.
• Ships as its own independently published package, consistent with the rest of the component suite (own README, changelog, license, example, and tests).

Acceptance criteria

• A consumer can manage a group catalog (create/edit/delete) and assign groups to users with minimal wiring.
• Deleting a group cleanly removes it from everyone it was assigned to.
• Long lists of groups and members are searchable.
• Appearance follows the host app's M3 theme and adapts across screen sizes.
• Demonstrated in the shared example catalog app and covered by tests.