Per-project task state lanes in the sidebar

[Eyalm321]

Type: AFK

What to build

Expand the per-project sidebar entry to show task lanes by state — Queued / Running (claimed) / Done / Failed / Dead — each with a live count, reusing the existing project→worktree disclosure pattern. This builds on the per-project badge by letting the user open a project and see where its tasks are in the pipeline.

Acceptance criteria

• Expanding a project reveals task lanes for each state with current counts
• Counts reflect the project's queue and refresh within ~2s
• Empty states render gracefully (zero-count or hidden)
• Visual style fits the existing sidebar disclosure (the worktree-row pattern)

Blocked by

• Per-project task count badge in the sidebar (queue↔project keystone) #6