Sidebar cards

Turn each sidebar row into a session card: name plus actions on one line, an adaptive meta line below carrying a colour-coded activity chip, duration, and any warning. Renders the activity dimension the daemon already infers (NAP-340) and adds an agent-reported Error state fed by a Claude Code hook. Both the web sidebar and the TUI sidebar implement one shared contract, docs/SIDEBAR.md. The PR chip is deliberately out of scope and belongs to its own milestone, since no forge integration exists yet.

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100% Completed