add synchronized dual-display workbench

frontend/src/components/shell/secondaryDisplayGeometry.ts

@@ -0,0 +1,40 @@
+export interface SecondaryDisplayGeometry {
+  left: number
+  top: number
+  width: number
+  height: number
+}
+
+function boundedInteger(value: unknown, minimum: number, maximum: number): number | null {
+  const parsed = typeof value === 'number' ? value : Number(value)
+  if (!Number.isFinite(parsed)) return null
+  return Math.min(maximum, Math.max(minimum, Math.round(parsed)))
+}
+
+export function parseSecondaryDisplayGeometry(value: string | null): SecondaryDisplayGeometry | null {
+  if (!value) return null
+  try {
+    const parsed = JSON.parse(value) as Partial<SecondaryDisplayGeometry>
+    const left = boundedInteger(parsed.left, -20_000, 20_000)
+    const top = boundedInteger(parsed.top, -20_000, 20_000)
+    const width = boundedInteger(parsed.width, 420, 3_840)
+    const height = boundedInteger(parsed.height, 520, 2_160)
+    return left === null || top === null || width === null || height === null
+      ? null
+      : { left, top, width, height }
+  } catch {
+    return null
+  }
+}
+
+export function secondaryDisplayFeatures(geometry: SecondaryDisplayGeometry): string {
+  return [
+    'popup=yes',
+    `left=${geometry.left}`,
+    `top=${geometry.top}`,
+    `width=${geometry.width}`,
+    `height=${geometry.height}`,
+    'resizable=yes',
+    'scrollbars=yes',
+  ].join(',')
+}