One component per file; GAME OVER offers CONTINUE

PRD G1 asks for one component per file. Eight files held two or
three; their eleven extra components move to files of their own,
helpers stay where both sides use them, and an archtest now fails
any file that holds two.

PRD 4.4 and the request say an error always offers CONTINUE.
ErrorState's button read RETRY; it now reads CONTINUE, under the
CONTINUE? countdown, on the crash screen and the lost page alike.

feedback/emptystate.go

@@ -0,0 +1,51 @@
+package feedback
+
+import (
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/display"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/input"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/text"
+)
+
+var openChest = pixel.MustSprite(`
+	..eeeeeeeeeeee..
+	.esssssssssssse.
+	.elllllllllllle.
+	..eeeeeeeeeeee..
+	................
+	eeeeeeeeeeeeeeee
+	ewwwwwwwwwwwwwwe
+	ewwwwwwwwwwwwwwe
+	eeeeeeeyyeeeeeee
+	essssssyysssssse
+	esssssssssssssse
+	eeeeeeeeeeeeeeee
+`)
+
+type EmptyStateOptions struct {
+	// Action labels a button; Acted reports it.
+	Action   string
+	Disabled bool
+}
+
+type EmptyStateResult struct {
+	Element *ui.Element
+	Acted   bool
+}
+
+// EmptyState shows NO ITEMS over an empty chest.
+func EmptyState(c *ui.Context, message string, o EmptyStateOptions) EmptyStateResult {
+	k := pixel.K(c)
+	res := EmptyStateResult{}
+	res.Element = ui.Column(c).Gap(k.D(6)).Padding(k.D(12)).AlignItems(ui.Center).Role(ui.RoleStatus).Label(k.Msg("empty")).Children(func() {
+		display.Sprite(c, openChest, display.SpriteOptions{Scale: 2})
+		text.ShadowText(c, k.Msg("empty"), text.ShadowTextOptions{Slot: pixel.Faint, Scale: 2})
+		pixel.Text(c, message, pixel.TextOptions{Slot: pixel.Faint})
+		if o.Action != "" {
+			res.Acted = input.Button(c, o.Action, input.ButtonOptions{Variant: input.Primary, Disabled: o.Disabled}).Clicked
+		}
+	})
+	return res
+}