Chat sidebar limits card-based conversation channels to 5 per category, remaining channels inaccessible

When a Card is created (in the Cards module), a corresponding conversation channel is automatically generated for it under the Chat module's sidebar, grouped by Card Type (e.g., Account, Partners, Product, Project). However, each category in the Chat sidebar only displays a maximum of 5 channels, even when more exist. There is no "show more" control, pagination, or scroll behavior to reveal the remaining channels — they appear to be completely inaccessible from the sidebar.

**Steps to Reproduce:**

- Create a custom Card Type (e.g., "Product") with more than 5 Cards.
- Open the Chat module.
- Observe the sidebar section corresponding to that Card Type.

**Expected behavior:**
All conversation channels for a given Card Type should be visible/accessible in the Chat sidebar, either through a "show more" expansion, scroll, or full list view.

**Actual behavior:**
Only the first 5 channels are shown per category. With 10 Cards under "Product," only 5 appear in the Chat sidebar, and there is no way to access the conversation channels for the remaining 5 from that view.

**Environment:**

- Huly version: 0.7.426 (self-hosted)
- Affected area: Chat sidebar / Card-generated conversation channels

No file or test is named. Reproduce the issue in the Chat sidebar with more than five Cards in one Card Type, then trace how card-generated conversation channels are listed; done means every channel is accessible through expansion, scrolling, pagination, or another full-list view.

Written by the indexing model from the issue text.