Summary

The /custom layout dialog gains a Section spacing selector controlling the vertical gap between the sidebar sections (blocks). The gap was previously hardcoded in the tab component (2 blank lines).

│  › Sidebar position                   ‹ Right ›  │
│    Section spacing                   ‹ Normal ›  │
│                                                  │
│  Sidebar sections                                │
│    [x] Token usage                               │
│    [x] Agents                                    │
│    [x] Tools                                     │
│    [x] Todos                                     │

Behavior

• Cycles with left/right arrows and previews live behind the dialog, exactly like the position selector; Enter persists, Esc restores
• Persisted as settings.layout.section_spacing in ~/.config/cagent/config.yaml; omitted when normal, and the whole layout entry is cleared when every setting is at its default
• Empty or unknown persisted values fall back to normal, so existing configs can never break the layout
• Spacing has no effect in the collapsed band (top/bottom) mode, which has no inter-block blank lines

Implementation

The tab header structure (title line + one padding line) is intentionally unchanged: it is load-bearing for click-zone offsets (tabHeaderLines, verticalStarY).

Testing

• New tests: dialog spacing cycling and live preview, rendered gap at 1/2/3 blank lines, agent click zones with a non-default gap, ParseSectionSpacing/BlankLines mapping, user config round trip and default omission
• go build ./..., golangci-lint run (0 issues), full pkg/tui/... and pkg/userconfig suites pass