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/agentstatus.go

@@ -0,0 +1,86 @@
+package agent
+
+import (
+	"cmp"
+	"math"
+	"slices"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type AgentStatusOptions struct {
+	// Portrait fits 12 dots square; zero means a robot.
+	Portrait *pixel.Sprite
+}
+
+// halo is the status ring's dots from twelve o'clock, clockwise.
+var halo = ring(17)
+
+// AgentStatus rings a portrait: idle, working, blocked or done.
+func AgentStatus(c *ui.Context, text string, s Status, o AgentStatusOptions) *ui.Element {
+	k := pixel.K(c)
+	face := portrait("AgentStatus", o.Portrait)
+	word, slot := s.look(k)
+	// The widest word sets the width, so it never jumps.
+	w := 40
+	for st := Idle; st <= Done; st++ {
+		wd, _ := st.look(k)
+		w = max(w, pixel.Measure(wd))
+	}
+	cx, cy := w/2, 18
+	return ui.Box(c).Size(k.D(w), k.D(52)).Role(ui.RoleStatus).Label(text).Description(word).Draw(func(p *ui.Painter, r ui.Rect) {
+		g := k.Canvas(p, r)
+		switch s {
+		case Idle:
+			for i, d := range halo {
+				if i%2 == 0 {
+					g.Dot(cx+d[0], cy+d[1], pixel.Faint)
+				}
+			}
+			// A sleepy Z drifts up; Reduce Motion holds it.
+			g.Micro(cx+13, 2-g.Step(4)%3, "Z", pixel.Faint, 1)
+		case Working:
+			// A busy arc chases round, even under Reduce Motion.
+			at := g.Busy(8) % 12 * len(halo) / 12
+			for i, d := range halo {
+				ink := pixel.Shade
+				if (i-at+len(halo))%len(halo) < len(halo)/4 {
+					ink = pixel.Info
+				}
+				g.Dot(cx+d[0], cy+d[1], ink)
+			}
+		case Blocked:
+			g.Circle(cx, cy, 17, pixel.Warn)
+			g.Rect(cx+12, 0, 7, 9, pixel.Warn)
+			g.Micro(cx+14, 2, "!", pixel.Ink, 1)
+		case Done:
+			g.Circle(cx, cy, 17, pixel.Good)
+			g.Circle(cx, cy, 16, pixel.Good)
+		}
+		g.Sprite(cx-face.W, cy-face.H, face, 0, pixel.Ink, 2)
+		g.Text((w-pixel.Measure(word))/2, 36, word, slot, 1)
+	})
+}
+
+// ring is a midpoint circle's dots, clockwise from the top.
+func ring(r int) [][2]int {
+	var pts [][2]int
+	x, y, e := r, 0, 1-r
+	for x >= y {
+		pts = append(pts, [2]int{x, y}, [2]int{y, x}, [2]int{-x, y}, [2]int{-y, x}, [2]int{x, -y}, [2]int{y, -x}, [2]int{-x, -y}, [2]int{-y, -x})
+		y++
+		if e < 0 {
+			e += 2*y + 1
+		} else {
+			x--
+			e += 2*(y-x) + 1
+		}
+	}
+	turn := func(p [2]int) float64 {
+		return math.Mod(math.Atan2(float64(p[0]), float64(-p[1]))+2*math.Pi, 2*math.Pi)
+	}
+	slices.SortFunc(pts, func(a, b [2]int) int { return cmp.Compare(turn(a), turn(b)) })
+	return slices.Compact(pts)
+}