v0.83.0: the publish-actions seam + EMAIL type widening

One new seam and a type widening. No consumer action required; both additive.

The publish-actions seam (new public surface)

A site can declare publishActions on its adapter's editor group — the adminNav grammar
applied to the publish-success moment. Entries are plain data ({ label, href, concepts? }),
href a template with {concept}/{id} substituted from the just-published entry, validated
fail-loud when the runtime composes. The edit page renders the resolved links as quiet
next-steps beside the publish confirmation. No callback crosses the publish redirect. New
types: PublishActionEntry, PublishActionsConfig, PublishActionLink. Worked example in
the SvelteKit reference: an /admin/club/announce?post={id} deep link.

EMAIL binding types widened

AuthEnv['EMAIL']'s send signature and MagicLinkMessage now carry optional cc/bcc
(EmailRecipient — bare address, named address, or arrays), single-address replyTo, and
typed attachments (EmailAttachment[]), matching the live Email Sending API. The platform
rejects reply-to arrays (live-probed 2026-07-07), so the type deliberately admits only the
single-address form. The original five-field shape stays valid everywhere.