Add agent components 451-465 and icon.Crystal

Fifteen components that dress an AI agent's work as an RPG party:
AgentCard, ToolCall, PlanQuest, ThinkingOrb, TokenMana, ApprovalPrompt,
AgentLog, SubAgentParty, MemoryCrystals, AgentStatus, DiffScroll,
ModelSelect, PromptBox, CostCoins and Checkpoints.

The context window is HP and the token budget MP; tool calls are spells
that CAST, glow, then land OK or FAILED; the transcript reads as a battle
log whose newest line types itself out; models line up like fighters.
Busy signs keep moving under Reduce Motion, decoration stops. Commands
and prompts never reach the log, and a veiled PromptBox casts nothing.

icon.Crystal is the new 12x12 save and memory crystal.

agent/subagentparty.go

@@ -0,0 +1,87 @@
+package agent
+
+import (
+	"fmt"
+	"slices"
+	"strings"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/icon"
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+// Member is a summoned agent and those it summoned.
+type Member struct {
+	Name     string
+	Status   Status
+	Summoned []Member
+}
+
+type SubAgentPartyOptions struct {
+	// Width is in dots; zero means 200.
+	Width int
+}
+
+// partyRow: a member, and per depth whether its branch ends.
+type partyRow struct {
+	m    Member
+	last []bool
+}
+
+// SubAgentParty draws the summoning tree, each agent with its status.
+func SubAgentParty(c *ui.Context, text string, party []Member, o SubAgentPartyOptions) *ui.Element {
+	k := pixel.K(c)
+	w := pixel.Or("SubAgentParty Width", o.Width, 200)
+	var rows []partyRow
+	var flat func(ms []Member, last []bool)
+	flat = func(ms []Member, last []bool) {
+		for i, m := range ms {
+			l := append(slices.Clone(last), i == len(ms)-1)
+			rows = append(rows, partyRow{m, l})
+			flat(m.Summoned, l)
+		}
+	}
+	flat(party, nil)
+	if len(rows) == 0 {
+		panic("agent: SubAgentParty has nobody")
+	}
+	said := make([]string, len(rows))
+	for i, r := range rows {
+		word, _ := r.m.Status.look(k)
+		depth := len(r.last) - 1
+		if need := depth*12 + 18 + 24 + pixel.Measure(word); r.m.Name == "" || w < need {
+			panic(fmt.Sprintf("agent: SubAgentParty member %q needs Width %d", r.m.Name, need))
+		}
+		said[i] = r.m.Name + ", " + word
+	}
+	return ui.Box(c).Size(k.D(w), k.D(len(rows)*pixel.LineHeight)).Role(ui.RoleImage).Label(text).Description(strings.Join(said, "; ")).Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		for i, row := range rows {
+			y, depth := i*pixel.LineHeight, len(row.last)-1
+			// Lines run from each summoner down to its summoned.
+			for a := 1; a < depth; a++ {
+				if !row.last[a] {
+					g.VLine((a-1)*12+5, y, pixel.LineHeight, pixel.Edge)
+				}
+			}
+			if depth > 0 {
+				x := (depth-1)*12 + 5
+				g.VLine(x, y, 8, pixel.Edge)
+				if !row.last[depth] {
+					g.VLine(x, y+8, pixel.LineHeight-8, pixel.Edge)
+				}
+				g.HLine(x, y+7, 7, pixel.Edge)
+			}
+			word, slot := row.m.Status.look(k)
+			x := depth * 12
+			g.Sprite(x, y+2, icon.Robot, 0, slot, 1)
+			if len(row.m.Summoned) > 0 {
+				g.VLine(x+5, y+14, 2, pixel.Edge)
+			}
+			ww := pixel.Measure(word)
+			g.Text(x+14, y, pixel.Wrap(row.m.Name, w-x-18-ww, 1)[0], pixel.Ink, 1)
+			g.Text(w-ww, y, word, slot, 1)
+		}
+	})
+}