Add chat components 321-345; named List rows, inert scroll views

Speech bubbles, a chat log that follows its end, a composer that sends
on Enter, typing dots, chat and channel lists, read receipts,
reactions, emoji and sticker pickers, mentions, date and unread rules,
system lines, member lists, user cards, a mailbox, mail reader and
letter, a notification bell, call controls, a voice meter, attachment
chips, link previews and polls.

pixel's editor takes EnterSends; display's Bubble takes a Fill and
exports EmojiSprite. data.List names its rows, which also lets typing
choose one. layout.ScrollArea and input.TextArea hold still under
Inert, and an inert scroll view leaves the Tab order until it wakes.

chat/reactions.go

@@ -0,0 +1,68 @@
+package chat
+
+import (
+	"fmt"
+	"log/slog"
+	"strconv"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+// Reaction is an emoji count; Mine marks your own.
+type Reaction struct {
+	Emoji string
+	Count int
+	Mine  bool
+}
+
+type ReactionsOptions struct {
+	Disabled bool
+}
+
+type ReactionsResult struct {
+	Element *ui.Element
+	// Toggled is the chip clicked this frame, else -1.
+	Toggled int
+}
+
+// Reactions shows emoji chips with counts; a click toggles yours.
+func Reactions(c *ui.Context, text string, rs []Reaction, o ReactionsOptions) ReactionsResult {
+	k := pixel.K(c)
+	res := ReactionsResult{Toggled: -1}
+	res.Element = ui.Row(c).Gap(k.D(2)).FocusGroup(ui.Horizontal).Role(ui.RoleGroup).Label(text).Children(func() {
+		for i := range rs {
+			r := &rs[i]
+			if r.Count < 0 || r.Mine && r.Count == 0 {
+				panic(fmt.Sprintf("chat: reaction %q counts %d, mine %v", r.Emoji, r.Count, r.Mine))
+			}
+			art := emoji(r.Emoji)
+			shell, base, st := pixel.Shell(c, func() *ui.Element {
+				return ui.ToggleBase(c, &r.Mine).Label(fmt.Sprintf("%s %d", r.Emoji, r.Count)).Disabled(o.Disabled).FocusRing(false)
+			})
+			if base.Changed() {
+				if r.Mine {
+					r.Count++
+				} else {
+					r.Count--
+				}
+				res.Toggled = i
+				slog.Debug("8bit: reaction toggled", "label", text, "emoji", r.Emoji, "mine", r.Mine)
+			}
+			n, mine := strconv.Itoa(r.Count), r.Mine
+			shell.Size(k.D(20+pixel.MicroWidth(n)), k.D(16)).Draw(func(p *ui.Painter, rc ui.Rect) {
+				g := k.Canvas(p, rc)
+				fill, ink := pixel.Face, pixel.Ink
+				if mine {
+					fill, ink = pixel.Accent, pixel.AccentInk
+				}
+				g.Frame(0, 0, g.W, g.H, pixel.Notched, fill)
+				g.Sprite(2, 2, art.sp, 0, art.ink, 1)
+				g.Micro(16, 6, n, ink, 1)
+				g.Finish(st)
+			})
+		}
+	})
+	return res
+}