fix(release): a dateless changelog header silently skipped the release

create-release aborted at [4/8] with "web/dist/neode-ui does not contain
v1.8.4-alpha — the frontend build no-opped or its output is stale". The
build had not no-opped: it was fresh, and simply had no 1.8.4 string to
embed.

sync-whats-new.py only matches '## vX.Y.Z (YYYY-MM-DD)'. The entry read
'## v1.8.4-alpha (draft — date set at cut)', so the version was invisible
to it: the gate's whats-new-sync stage reported "87 versions, all present"
while the release being cut had no What's New block. That modal is the
only place a version string appears in the frontend, so the bundle carried
none and the freshness check — correctly — refused it, while naming the
wrong cause. Step [5/8] only greps for '^## v1.8.4-alpha (' so it passed
the draft too.

Three changes: date the v1.8.4-alpha entry, insert the modal block it was
owed, and make the sync tool refuse any version header without a real date
instead of skipping it. Skipping is what let a wrong "all present" through.

Verified: the draft header now fails the check with an explicit message,
the dated one passes (88 versions, up from 87), and a rebuilt bundle
contains 1.8.4-alpha where it did not before.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## v1.8.4-alpha (draft — date set at cut)
+## v1.8.4-alpha (2026-08-20)
 
 - **Apps with their own login can now skip the node's login screen — Gitea and BTCPay Server do so out of the box.** Some apps bring a complete account system of their own, and putting the node's password page in front of them broke real workflows: git clients can't answer a browser login, and a BTCPay checkout link handed to a customer must open for that customer. These apps are now served directly on their own login, while the node still fronts the connection for everything else it does (embedding fixes, the "app is restarting" page, Tor). Every app gets a new **Settings → app → Access control** switch, so you can put the node login back in front of any app — or take it away from one — with one click, effective immediately. App developers declare the default in their manifest (`auth: open`), documented in the developer guide.