dMsg 1.1.1

chore(proposals): add proposal 570 to release dmsg_frontend v3.4.5

Execute commit_proposed_batch() for batch 83 on dmsg_frontend. The summary
lists the v3.4.5 changes: iOS sign-in through the fixed HTTPS callback, the
apple-app-site-association file for S9Z2WAMAV8.net.dmsg.ios, the callback
page that keeps nothing, and the six-language texts. Batch 83 and its
evidence are kept as supplied.

Validation: bash -n passes and the summary encodes as Candid text with didc.
quill was not run, and the batch ID and evidence were not checked against a
build of this commit.

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