Refine hook activity rendering in the TUI

[copyberry]

Refine hook activity rendering in the TUI

What changed

• Show revealed running hooks in the bottom activity area instead of the conversation viewport or transcript overlay. Fold the hook message into the active status row when space permits and reflow it below the row without displacing background-process controls or status details.
• Keep fast hooks hidden, collapse concurrent hooks to a shared summary when needed, and support hook activity outside an active agent turn.
• Simplify durable hook output into user-facing messages and actionable failure, block, and stop states. Suppress model-facing context and quiet successful completions from all TUI history surfaces.

Testing

• Add lifecycle, layout, narrow-width, multi-width Unicode, transcript, restart, and completion-output coverage for hook status and history rendering.