feat: add enhanced mentions

[MartinCupela]

Goal

Provide support for enhanced mentions:

• @here
• @channel
• @user
• @userRole
• @userGroup

Summary

It introduces full typed User Group client support, including CRUD/member-management methods and a dedicated UserGroupPaginator, then extends the composer mention pipeline so @ suggestions can return a mixed typed set of users, built-in mentions, roles, and user groups. On selection and send/draft composition, those tracked mention entities are mapped into the correct message fields: mentioned_users, mentioned_channel, mentioned_here, mentioned_roles, and mentioned_group_ids.

Refactors mention normalization into a shared mentionUtils helper, updates search behavior to use the user-group search endpoint only for mention autocomplete, and adds focused regression coverage for the new API surface, paginator behavior, mixed mention suggestions, and send/draft payload generation.

Highlights

• Add typed StreamChat user-group API methods:
  • queryUserGroups
  • createUserGroup
  • getUserGroup
  • searchUserGroups
  • updateUserGroup
  • deleteUserGroup
  • addUserGroupMembers
  • removeUserGroupMembers
• Add UserGroupPaginator for cursor-based user-group listing
• Extend mention suggestions to support:
  • direct users
  • @channel
  • @here
  • roles
  • user groups
• Track mentions through a unified typed mention-entity model
• Map tracked enhanced mentions into send and draft payload fields
• Restrict user-group endpoint usage to autocomplete/search flow only

Todo:

Waiting for back-end support:

• support for mentioned groups enrichment from server in message response - so that group name and description can be displayed
• possibility to search for roles so that they can be suggested for mentions

[github-actions]

Size Change: +13.8 kB (+3.6%)

Total Size: 399 kB

📦 View Changed

Filename	Size	Change
dist/cjs/index.browser.js	133 kB	+4.61 kB (+3.6%)
dist/cjs/index.node.js	134 kB	+4.62 kB (+3.57%)
dist/esm/index.mjs	132 kB	+4.61 kB (+3.62%)

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