iOS: CarPlay (#420)

A CarPlay scene beside the phone's: In Progress, Unread and Shows as
CPListTemplates from ipx's API, read with the player's credentials, and
a pick played through the same Playback, so it resumes from the saved
place, saves as it goes and marks read at 90%. Now Playing is the
system's template over Playback's now-playing info.

When the car starts a different episode the page is sent
{t:"replaced"} and closes its player bar. Left open, the bar would have
gone on as the old episode while the host's clock belonged to the new
one, saving that time and marking the wrong item read.

The badge's fetch moves into API.get, which CarPlay shares. Build 13.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

ios/CHANGELOG.md

@@ -13,6 +13,7 @@ The iOS app, `ios/`. Format: [Keep a Changelog](https://keepachangelog.com/en/1.
 - A sleep timer in the player, kept by the phone, so it pauses on time with the screen locked, fading out over the last ten seconds; and an AirPlay button beside it, for another speaker or a TV (#429).
 - iPX opens with no connection, showing the lists it last had, as it does in a browser: the page's service worker now runs in the app. This is for `ipodderx.sdf1.net` only, and links to other sites open in Safari (#435).
 - Siri and Shortcuts: "Resume iPX", "Pause iPX", "Skip forward in iPX", "Skip back in iPX", "Set a sleep timer in iPX" and "How many unread in iPX", with nothing to set up, and each an action in Shortcuts. Resume works with the app closed, carrying on with the last episode from where you left off (#427).
+- CarPlay: In Progress, Unread and Shows on the car's screen, an episode playing from where you left off and saving its place as it does on the phone, and the car's Now Playing for the rest (#420).
 - A widget for the home screen and lock screen: the unread count, and the episode you were on with a button to resume or pause it (#428).
 - The icon's count stays right with the app closed: ipx sends it to the phone when it changes, once its `[push]` is set up, in place of waiting for iOS's background refresh (#433).
 - Presses are felt: a light tap on play, pause, flag and pull to refresh, a success on marking read, a warning with an error (#430).