MITHOME-68: the optimistic-lock fingerprint was frozen at page load, so the
user's own second save 409'd. /save now returns the hash of the written
content and the client refreshes CONTENT_HASH on success — 409 only fires
for genuine external changes (deploy, other tab, restore). Also: successful
logins no longer consume the auth failure budget (only failed attempts do).
MITHOME-69: bottom bar items no longer shift while saving/publishing — the
status message occupies a constant flex slot (visibility instead of
display), the publish button locks its width while running and restores
its env-specific label, auto margins removed. Layout guard test added.
Test markers are now run-unique so a crashed run can never poison the
next one's expectations.
A Content Editor tab left open across a deploy (or a save from another tab)
held the pre-deploy content; one Save would silently overwrite the newer
file. The editor page now embeds a SHA-256 fingerprint of the file content
at load time, /save requires it back in X-Content-Hash and compares against
the current file: mismatch (or a missing header) answers 409 with an
explanatory message and writes nothing. The client offers a reload on 409.
Integration test covers: matching hash saves, stale hash rejected with the
file untouched, missing hash rejected, retry with the fresh hash succeeds.
Closes MITHOME-61
Do Siki