FIX - modernize lock screen passcode flow

Rebuild device unlock around the current iOS-style wallpaper, outlined keypad, telephone letters, status bar, and keyboard support. Require the passcode only for the first unlock of each open device session so a soft lock from the status bar returns directly after the session is authenticated.

frontend/src/components/PhonePasscode.contract.test.ts

@@ -0,0 +1,34 @@
+import { readFileSync } from 'node:fs'
+
+import { describe, expect, it } from 'vitest'
+
+const source = readFileSync(
+  new URL('./PhonePasscode.vue', import.meta.url),
+  'utf8',
+)
+
+describe('PhonePasscode iOS presentation contract', () => {
+  it('uses the Lock Screen wallpaper and status bar for device unlocks', () => {
+    expect(source).toContain('lockScreen?: boolean')
+    expect(source).toContain('settings.lockWallpaperImageUrl')
+    expect(source).toContain(
+      'wallpaper--${phone.preferences.settings.lockWallpaper}',
+    )
+    expect(source).toContain('<PhoneStatusBar v-if="lockScreen"')
+  })
+
+  it('renders the telephone letters and accessible native-size controls', () => {
+    expect(source).toContain("{ digit: 2, letters: 'ABC' }")
+    expect(source).toContain("{ digit: 7, letters: 'PQRS' }")
+    expect(source).toContain('min-height: var(--sky-touch-target)')
+    expect(source).toContain('passcode-screen__footer')
+    expect(source).toContain('--passcode-key-background: transparent')
+    expect(source).toContain('@keydown="handleKeydown"')
+  })
+
+  it('keeps light, dark and reduced-motion treatments explicit', () => {
+    expect(source).toContain(':global(.phone-app--light)')
+    expect(source).toContain('@media (prefers-reduced-motion: reduce)')
+    expect(source).toContain('passcode-screen__backdrop')
+  })
+})