feat(tui): responsive three-column layout with status bar

Author: engalar

tui/layout.go

@@ -0,0 +1,37 @@
+package tui
+
+import (
+	"fmt"
+
+	"github.com/charmbracelet/lipgloss"
+)
+
+// columnWidths returns [modulesW, elementsW, previewW] given total terminal width.
+func columnWidths(totalW int) (int, int, int) {
+	// Reserve 2 chars per border (left+right) × 3 columns = 6
+	available := totalW - 6
+	if available < 30 {
+		available = 30
+	}
+	modulesW := available * 20 / 100
+	elementsW := available * 30 / 100
+	previewW := available - modulesW - elementsW
+	return modulesW, elementsW, previewW
+}
+
+// renderLayout assembles the three panels + status bar into the full screen.
+func renderLayout(
+	totalW int,
+	modulesView, elementsView, previewView string,
+	statusLine string,
+) string {
+	status := lipgloss.NewStyle().
+		Background(lipgloss.Color("236")).
+		Foreground(lipgloss.Color("252")).
+		Width(totalW).
+		Render(statusLine)
+
+	cols := lipgloss.JoinHorizontal(lipgloss.Top, modulesView, elementsView, previewView)
+
+	return fmt.Sprintf("%s\n%s", cols, status)
+}