feat(chat): add configurable channel bots with Chat SDK

[m43i]

Feature Request

Problem

KIWI should support configurable AI bots that can participate in channels and answer questions using selected knowledge graph context. The current chat experience is user-driven, but teams need reusable bot personas that administrators can configure centrally and attach to channel workflows.

Proposed Solution

Integrate Chat SDK (https://chat-sdk.dev/) as the foundation for channel-aware bots in KIWI.

The implementation should provide a composable bot configuration model that allows system administrators to define reusable bots with their own behavior, model settings, instructions, and graph access. Bots should be attachable to channels with a specific team context and one or more knowledge graphs. When a bot is mentioned in a channel, it should generate an answer in that channel using the configured graph scope.

Requirements

• Add an administration flow for creating, updating, and disabling bot configurations.
• Allow bot definitions to include identity, description, instructions, model/runtime configuration, and access constraints.
• Allow bots to be associated with a team and one or more knowledge graphs when added to a channel.
• Support adding and removing configured bots from channels.
• Trigger bot responses only when the bot is explicitly mentioned in a channel message.
• Ground bot answers in the configured graph scope and enforce existing team, graph, and authorization boundaries.
• Persist bot configuration, channel membership, and graph associations.
• Ensure bot responses integrate with the existing channel message flow and streaming UX where appropriate.
• Provide clear error handling when a bot lacks access to a graph, is disabled, or cannot generate a response.

Acceptance Criteria

• An administrator can configure reusable bots.
• A channel can include one or more configured bots.
• Each channel bot instance can be scoped to a team and multiple graphs.
• Mentioning a bot in a channel causes it to respond in that channel.
• Bot responses use only the graphs and permissions configured for that channel context.
• The implementation includes API, persistence, and frontend support.
• Relevant tests or verification steps are added for bot configuration, channel membership, mention handling, and permission enforcement.

Technical Notes

• Evaluate how Chat SDK should compose with the existing AI SDK-based model infrastructure.
• Reuse existing graph retrieval and authorization mechanisms where possible.
• Prefer a data model that separates reusable bot definitions from per-channel bot assignments.
• Keep the integration extensible for future bot capabilities beyond mention-based replies.