feat(folio-web): web sample app + CDP spec tests (#36)

* fix(runner): allow nil connection for web platform

* fix(testrun): skip SDK handshake for web platform

* feat(folio-web): add React/Vite web sample app

* feat(folio-web): add sanderling spec

* fix(chrome): use InsertText for multi-char text input

* feat(hierarchy): add Screen field populated from sanderling-screen attr

* fix(chrome): auto-detect viewport from CSS vars, fix InputText accumulation, expose route as screen

* fix(runner): fall back to hierarchy root screen when snapshot screen is empty

* fix(folio-web): broaden loggedIn extractor to all authenticated pages

examples/folio-web/src/format.ts

@@ -0,0 +1,67 @@
+import type { Transaction } from './db'
+
+const CURRENCY = '$'
+
+export function formatCents(
+  cents: number,
+  opts: { signed?: boolean } = {},
+): string {
+  const abs = Math.abs(cents)
+  const dollars = Math.floor(abs / 100)
+  const rem = abs % 100
+  const dollarsStr = dollars.toLocaleString('en-US')
+  const formatted = `${CURRENCY}${dollarsStr}.${rem.toString().padStart(2, '0')}`
+  if (cents < 0) return `-${formatted}`
+  if (opts.signed && cents > 0) return `+${formatted}`
+  return formatted
+}
+
+export function parseCents(input: string): number | null {
+  const trimmed = input.trim().replace(/,/g, '')
+  if (trimmed === '') return null
+  if (!/^\d+(\.\d{1,2})?$/.test(trimmed)) return null
+  const [whole, frac = ''] = trimmed.split('.')
+  const fracPadded = (frac + '00').slice(0, 2)
+  const total = Number(whole) * 100 + Number(fracPadded)
+  if (!Number.isFinite(total) || !Number.isInteger(total)) return null
+  if (total > Number.MAX_SAFE_INTEGER) return null
+  return total
+}
+
+export function signedAmount(t: Transaction): number {
+  return t.type === 'credit' ? t.amount : -t.amount
+}
+
+export function balanceOf(txns: Transaction[]): number {
+  let total = 0
+  for (const t of txns) total += signedAmount(t)
+  return total
+}
+
+export function initialsOf(name: string): string {
+  const parts = name.trim().split(/\s+/).filter(Boolean)
+  if (parts.length === 0) return '?'
+  if (parts.length === 1) return parts[0].slice(0, 2).toUpperCase()
+  return (parts[0][0] + parts[parts.length - 1][0]).toUpperCase()
+}
+
+const DATE_FMT = new Intl.DateTimeFormat('en-US', {
+  month: 'short',
+  day: 'numeric',
+  hour: 'numeric',
+  minute: '2-digit',
+})
+
+export function formatDate(ts: number): string {
+  return DATE_FMT.format(new Date(ts))
+}
+
+const CLOCK_FMT = new Intl.DateTimeFormat('en-US', {
+  hour: 'numeric',
+  minute: '2-digit',
+  hour12: false,
+})
+
+export function formatClock(ts: number): string {
+  return CLOCK_FMT.format(new Date(ts))
+}