User Settable Limit for Cards per Column

One of the key principles of Kanban methodology is the ability to limit work in progress. This can be visualised by setting a limit to the number of cards in a column. For example, the Work in Progress column may be set to have a limit of only five cards.

The default setting for any column should be infinite, e.g. the Backlog can have as many cards as needed.

The card limit, and the number of cards currently in the column should be displayed, e.g. 3/5

Perhaps this could be set by users in the Kanban note via YAML front-matter or similar.

Start by locating the Kanban column rendering, card-count display, and handling for Kanban note YAML front-matter. Define how a per-column limit is configured, preserving an unlimited default, then verify that each column shows its current count and configured limit and prevents work in progress from exceeding that limit.

Written by the indexing model from the issue text.