feat: CRUD DMR talk groups and TG lists (incl. TG ↔ TGL)

[pskillen]

Problem

DMR talk groups and TG lists can only be viewed, not managed.

Intended outcome

Full create / read / update / delete for DMR talk groups and TG lists against the internal data models, including adding and removing a TG to/from a TG list (TG ↔ TGL).

• Add, edit, and delete talk groups.
• Add, edit, and delete TG lists.
• Manage TG ↔ TG-list membership.
• Keep references consistent when a TG or TGL is renamed/deleted (channels may reference TG lists).

Affected tool(s)

• Tools under tools/ plus shared model/state code.

Notes

• Depends on internal data models (genericise-import) and LocalStorage persistence.
• Note distinction from digital contacts (separate ticket): under the hood TG = group call to a DMR ID; contact = private call to a DMR ID.