TUI: improve activity panel with structured progress and last-run summary

[rmanibus]

Summary

The TUI activity panel still behaves mostly like a rolling text log.

We should evolve it into a structured status area that shows current phase, counters, and the latest action outcome in a more stable layout.

Scope

• Add structured activity/progress state to the TUI model
• Show current phase for running actions
• Show useful counters when available
• Show the latest success/failure state and timestamp
• Keep recent log lines below the structured header
• Update tests for live activity rendering and action completion summaries

Why

• Makes long-running actions easier to follow
• Reduces noise from raw log output
• Gives the TUI a more intentional operator dashboard feel

Related: #132, #211, #213