feat(appstore): script the provisioning, listing and TestFlight setup

The listing copy lives in text files rather than in a web form, so changing a description is a diff
someone can read and the store listing is reviewable next to the code it describes. Field lengths
are checked before sending, because Apple rejects an over-length field with an error that never
names the limit.

apple-provision.rb drives the Developer Portal through spaceship and is find-or-create throughout.
That matters most for the Developer ID certificate: an account may hold only a handful, they cannot
be un-revoked, and every copy of the app already signed by one stops verifying if it goes away.

Both scripts pin the App Store Connect team. This Apple ID can see more than one, and the other
belongs to somebody else entirely, so letting spaceship choose is how a listing ends up on the
wrong account.

The reviewer phone number and email are deliberately not in here. Apple requires a real number and
this repo is public.

Claude-Session: https://claude.ai/code/session_018HwEWvoE1NkkUjJCMLSnup

appstore/metadata/en-US/keywords.txt

@@ -0,0 +1 @@
+writing,writer,editor,text,document,offline,grammar,typography,epub,pdf,author,manuscript,draft