Correct TUI workflows and add panel resizing

Implement LAB-226, LAB-232 and LAB-233 with shared resize controls, asynchronous MQTT results, clear topic states and additive selection.

Preserve legacy input and paste while supporting distinct Ctrl+Enter. Fix independently reviewed layout, history and headless trace issues.

Verified vet, full tests/race, cross-builds and live PTY smoke. Plans and interaction/layout regression coverage are included.