conversation-groups

Organize the user's conversations into sidebar groups. Groups are the sections shown in the conversation sidebar; each conversation belongs to exactly one group. ## Groups - **Custom groups** are user-defined sections (e.g. "Work", "Travel planning"). Create them with `conversation_group_create` and file conversations with `conversation_move_to_group`. - **System groups** are built in and cannot be created, renamed, or deleted: - `system:pinned` (Pinned) — moving a conversation here pins it; moving it elsewhere unpins it. - `system:all` (Recents) — the default ungrouped section. Move a conversation here to "remove" it from a custom group. - `system:scheduled` (Scheduled) and `system:background` (Background) — hold automated conversations. Moving a conversation into these demotes it out of the Recents listing; avoid unless the user explicitly asks. ## Usage - When mentioning a conversation in Vellum chat, link it as `[Title](/assistant/conversations/<id>)`. Use that path only in Vellum chat. Do not use it in Slack, Telegram, Discord, email, or notifications. - `conversation_move_to_group` defaults to the **current** conversation, so "file this chat under Work" needs no conversation id. - Groups can be referenced by name (case-insensitive) or id. Prefer names; fall back to ids when names are ambiguous. - When the user asks to organize their conversations, check the existing groups first (`conversation_group_list`) and reuse a fitting group rather than creating near-du...