add chat component and claude ui-max-pro skill

[maks5554371]

Introduces a composable Ui::Chat component to the UI library. The component covers a message feed with bubbles, avatars, author/timestamp, a typing indicator, and an input footer - plus auto-scroll and a Turbo Streams integration point for realtime updates.

Component API

<%= ui.chat stream: [@room, :messages] do %>
  <%= ui.chat_messages id: dom_id(@room, :messages) do %>
    <%= ui.chat_message position: :start do %>
      <%= ui.avatar user: message.user %>
      <%= ui.chat_bubble do %>
        <%= ui.chat_author message.user.full_name %>
        <%= message.body %>
        <%= ui.chat_time message.created_at.strftime("%H:%M") %>
      <% end %>
    <% end %>
    <%= ui.chat_message position: :end do %>
      <%= ui.chat_bubble variant: :primary do %>How are you?<% end %>
    <% end %>
    <%= ui.chat_typing %>
  <% end %>
  <%= ui.chat_footer do %> … message form … <% end %>
<% end %>

Subcomponents
chat, chat_messages, chat_message (position: :start/:end), chat_bubble (variant: :default/:primary/:muted), chat_author, chat_time, chat_typing, chat_footer.

Interactivity (chat_controller.js)

Auto-scroll to the latest message via MutationObserver, respecting manual scroll-up (only auto-scrolls when the user is pinned to the bottom).

Enter to send (Shift+Enter for a newline) via the send action on the message form.

Textarea auto-grow is wired through the existing textarea-autogrow controller.

Realtime
The stream: option renders turbo_stream_from, and chat_messages exposes a stable DOM id as the broadcast target - so a model can broadcast_append_to new messages and they appear live (with auto-scroll). No backend/ActionCable is added here; the component only provides the integration points, documented in the component docs.

Documentation
Full docs at /ui/components/chat via component.yml (props, slots, examples), a docs view, route, breadcrumb, sidebar link, and a controller action

Tooling: ui-ux-pro-max Claude skill
Also bundles a Claude Code skill under .claude/skills/ui-ux-pro-max/ - a UI/UX design knowledge base (styles, palettes, font pairings, stack-specific guidelines) with helper scripts, used to assist component design and review within the repo.

[solilin]

Let's rename it ro streams, and it should be an Array [] by default

[solilin]

data_attributes is for data, but there could be other attributes also, for example, class, id, ...

Let's merge data attributes separately.

[solilin]

.block_name {}
.block_name__element_name {}
.block_name__element_name-mod {}

[solilin]

Seems, that is should be a private - #scrollToBottom