Show in-flight request count + activity spark on In-Flight Monitor key

The key now renders the live request count (large) when a model is active,
plus a 1Hz count-trend sparkline of the last 60s in a bottom strip. IDLE/
LOADING/OFF/OFFLINE states unchanged. History lives in per-key state with
a sampler cleared on disappear.

src/lib/render.ts

@@ -20,6 +20,7 @@ export interface InflightRenderOptions {
   count: number;
   offline: boolean;
   pulse: boolean;
+  history?: number[];
 }
 
 export function renderInflight(opts: InflightRenderOptions): string {
@@ -46,13 +47,26 @@ export function renderInflight(opts: InflightRenderOptions): string {
 
   const isActive = opts.state === "ready" && opts.count > 0;
   const bg = opts.state === "ready" ? (isActive ? "#8b2626" : "#1e6b34") : opts.state === "loading" ? "#8a6d1d" : "#3a3a3a";
-  const label = opts.state === "ready" ? (isActive ? "ACTIVE" : "IDLE") : opts.state === "loading" ? "LOADING" : "OFF";
+  const center = isActive ? `${opts.count}` : opts.state === "ready" ? "IDLE" : opts.state === "loading" ? "LOADING" : "OFF";
+  const centerSize = isActive ? 24 : 16;
   const opacity = isActive && opts.pulse ? 0.55 : 1;
 
-  return frame(bg, [
-    centerText(label, 38, 18, "bold", "#ffffff", opacity),
-    centerText(name, 64, 7, "normal", "#ffffff"),
-  ]);
+  const parts: string[] = [
+    centerText(name, 12, 7, "normal", "#ffffff"),
+    centerText(center, 40, centerSize, "bold", "#ffffff", opacity),
+  ];
+
+  if (opts.state === "ready") {
+    const points = inflightSparkPoints(opts.history ?? []);
+    if (points.length > 1) {
+      parts.push(
+        `<path d="M ${points.map((p) => `${p.x},${p.y}`).join(" L ")} L ${points[points.length - 1].x},63 L ${points[0].x},63 Z" fill="#ffffff" opacity="0.18"/>`,
+        `<polyline points="${points.map((p) => `${p.x},${p.y}`).join(" ")}" fill="none" stroke="#ffffff" stroke-width="1.5" stroke-linejoin="round" stroke-linecap="round" opacity="0.8"/>`,
+      );
+    }
+  }
+
+  return frame(bg, parts);
 }
 
 export interface GpuGraphRenderOptions {
@@ -132,6 +146,22 @@ function chartPoints(history: number[], metric: GpuMetricKind): { x: number; y:
   });
 }
 
+function inflightSparkPoints(history: number[]): { x: number; y: number }[] {
+  const n = history.length;
+  if (n === 0) return [];
+  const left = 4;
+  const right = 68;
+  const top = 50;
+  const bottom = 63;
+  const yMax = Math.max(...history, 1);
+  return history.map((v, i) => {
+    const x = n === 1 ? (left + right) / 2 : left + ((right - left) * i) / (n - 1);
+    const clamped = Math.max(0, Math.min(v, yMax));
+    const y = bottom - (clamped / yMax) * (bottom - top);
+    return { x: round1(x), y: round1(y) };
+  });
+}
+
 function yScaleMax(metric: GpuMetricKind, history: number[]): number {
   if (metric !== "power") return 100;
   const maxValue = Math.max(...history);