Help screen: wrap descriptions under themselves, size to the terminal

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/ui/help_test.go

@@ -0,0 +1,62 @@
+package ui
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/rivo/tview"
+)
+
+func TestRenderHelpFitsAndAligns(t *testing.T) {
+	for _, width := range []int{40, 60, 76, 96} {
+		text := renderHelp(width)
+		var inItem bool
+		for i, line := range strings.Split(text, "\n") {
+			if w := tview.TaggedStringWidth(line); w > width {
+				t.Errorf("width %d, line %d is %d columns wide: %q", width, i, w, line)
+			}
+			plain := plainText(line)
+			// Descriptions wrap under themselves: a continuation line starts with
+			// spaces up to the description column, never at the left edge.
+			switch {
+			case plain == "":
+				inItem = false
+			case !strings.HasPrefix(plain, " "):
+				inItem = false // a section title
+			case strings.HasPrefix(plain, strings.Repeat(" ", 2+helpKeyWidth)) && strings.TrimSpace(plain) != "":
+				if !inItem {
+					t.Errorf("width %d: continuation without an item before it: %q", width, plain)
+				}
+			default:
+				inItem = true
+			}
+		}
+		// Nothing is lost.
+		for _, sec := range helpSections {
+			if !strings.Contains(text, sec.title) {
+				t.Errorf("width %d: section %q missing", width, sec.title)
+			}
+			for _, it := range sec.items {
+				first := strings.Fields(it.desc)[0]
+				if !strings.Contains(plainText(text), first) {
+					t.Errorf("width %d: description of %q lost", width, it.keys)
+				}
+			}
+		}
+	}
+}
+
+func TestRenderHelpKeepsEveryWord(t *testing.T) {
+	desc := "Changes apply live behind the dialog, also while you move through an open list"
+	words := strings.Fields(desc)
+	text := plainText(renderHelp(50))
+	// Join the wrapped lines of the long Library "F" description and look for every word in order.
+	pos := 0
+	for _, w := range words {
+		i := strings.Index(text[pos:], w)
+		if i < 0 {
+			t.Fatalf("word %q missing or out of order", w)
+		}
+		pos += i + len(w)
+	}
+}