Advertise the rule screens in the key help

The bottom help still described 4 as "rules" from before the rules list
existed, and never mentioned 5 at all, so the new screen was unreachable
unless you already knew about it.

The transactions line had also outgrown the window: at 137 characters it ran
past the edge of a normal terminal and "q quit" was simply gone. Help now
wraps to the window width instead of being cut off, and that line is shorter.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

internal/tui/tui_test.go

@@ -840,6 +840,55 @@ func TestRuleListPruneWithNothingToDo(t *testing.T) {
 	}
 }
 
+// Every screen must advertise how to reach the others and how to quit. These
+// lines drift as screens are added, and a line that outgrows the terminal
+// loses its tail silently.
+func TestHelpLinesMentionEveryScreen(t *testing.T) {
+	m, _ := newTestModel(t)
+
+	for _, tc := range []struct {
+		name string
+		key  string
+		want []string
+	}{
+		{"accounts", "1", []string{"4 new rule", "5 rules", "q quit"}},
+		{"transactions", "2", []string{"4 new rule", "5 rules", "q quit"}},
+		{"report", "3", []string{"4 new rule", "5 rules", "q quit"}},
+		{"rules", "5", []string{"d delete rule", "p prune all unused", "4 new rule", "q quit"}},
+	} {
+		key(t, m, tc.key)
+		help := m.help()
+		for _, want := range tc.want {
+			if !strings.Contains(help, want) {
+				t.Errorf("%s help = %q, missing %q", tc.name, help, want)
+			}
+		}
+	}
+
+	// The rule builder is a form, so it advertises its own keys instead.
+	key(t, m, "4")
+	if help := m.help(); !strings.Contains(help, "enter save rule") || !strings.Contains(help, "esc back") {
+		t.Errorf("rule builder help = %q", help)
+	}
+}
+
+// A help line longer than the window must wrap, not be cut off.
+func TestHelpWrapsOnNarrowTerminals(t *testing.T) {
+	m, _ := newTestModel(t)
+	key(t, m, "2")
+	m.Update(tea.WindowSizeMsg{Width: 90, Height: 30})
+
+	view := m.View()
+	if !strings.Contains(view, "q quit") {
+		t.Errorf("the end of the help line was lost at 90 columns:\n%s", view)
+	}
+	for _, line := range strings.Split(view, "\n") {
+		if len([]rune(line)) > 90 {
+			t.Errorf("line is %d columns wide, wider than the window:\n%q", len([]rune(line)), line)
+		}
+	}
+}
+
 // newEmptyModel builds a model over an index with nothing in it.
 func newEmptyModel(t *testing.T, accounts []*config.Account) *Model {
 	t.Helper()