[Feature]: Kanban Mode

[mhenke]

Originally tracked in issue #713.

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Description

Lets add "slim" way

Extra context

No response

[mhenke]

@mhenke originally wrote:

Here is a spec for Kanban Mode, worked up from the original idea. Short version: a live task board in the TUI sidebar that shows what the background agents are actually doing.

What it is
The plugin already tracks every background task in an in-memory board (BackgroundJobBoard). Kanban Mode is just a view over that data, so there is no new data model to design. Flip on kanbanMode in the config and the sidebar gets replaced by columns: Running, Completed, Failed, Cancelled, and Done. Each card shows the agent, the task description, and how long it has been running. Read only for now, no buttons.

The one gotcha
The TUI runs in a separate process from the plugin, so it cannot read the board straight from memory. We already solve this for agent model info: the main process writes a snapshot to tui-state.json and the TUI reads it once a second. Kanban reuses that exact path. The main process serializes the board on every status change, the TUI parses it on its existing timer. Writes go through a temp file and a rename, so if the TUI reads mid-write it just shows an empty board for one cycle. All told it is a couple hundred lines, mostly in tui.ts and tui-state.ts.

What I need from you
Three small calls before anyone builds this:

1. When a failed job gets reconciled, should it move to Done like the others, or stay in Failed until the session ends?
2. Should the Done column clear itself after a while, or stick around until you restart?
3. On failed cards, show a short result snippet (about 60 chars) or leave them bare?

That is the whole thing. Happy to hand it to a fixer once those are settled.

[mhenke]

@alvinunreal originally wrote:

tui kanban wont work well more persisten kanban, open opencode, have web server, use .slim and let orchestrator fill kanban with the user requests and orchestrator pricessing

[mhenke]

@adikpb originally wrote:

https://x.com/thdxr/status/2077079272166961195

What if we put this off till this happens? Wont need another process running. Maybe even have interview moved into this if possible.