Attention inbox: one surface for everything that needs the human

[liam-russell]

Problem

As soon as several worktrees have agents in flight, "what needs me right now?" is scattered across surfaces: blocked sessions (#140), workers awaiting review (#136), failing checks (#138), unresolved review comments (#139). The user ends up polling worktrees one by one — exactly the context-switching the worktree-first model is supposed to remove.

Proposal

A single attention inbox: a badge count in the workspace header opening a panel of actionable items.

• Each item: type icon, worktree/branch, age, one-line context, and a jump-straight-to-the-action click target (the permission prompt, the review diff, the failing check, the comment thread).
• Ranked by what's blocking the most work — a permission prompt stalling a fan-out subtask outranks a stale review comment.
• Keyboard triage (j/k + enter), mark-as-done where the source allows it.
• The same item stream feeds OS notifications (OS notification when a background agent session finishes #92), so in-app and native notifications can't drift apart.

Scope: aggregation + navigation only — each item type is produced by its own feature issue.