fix: the chat tab no longer scrolls, and a group is listed or invite-only

**The chat tab was 8px too tall, at every window size.** The panel is sized from
JS to `viewport - top - 16`, which puts its bottom 16px above the fold — but it
sits inside `.main`, which adds 24px of padding below it. Eight pixels of
document past the window, whatever the window. Measured at 700, 900 and 1200:
`scrollHeight` 708, 908, 1208.

This is the second one of these — the sign-in card was `.page-center` and
`.layout` each reserving `100vh - 52px` — so it is now measured in the suite
rather than reasoned about. `tests/harness/scroll_probe.py` renders the real
markup against the real stylesheet and **runs the real `fit()` lifted out of
`app.js`**: a copy of the formula in a test would go on passing after the
original changed, which is exactly the bug being guarded.

The fix does not encode 24 anywhere. The first pass runs as before, then the
leftover is measured and taken off, so anything added below the panel later is
absorbed the same way. Now `scrollHeight == innerHeight` at all three heights,
nothing below the fold, and the panel still fills the room it has — that last
one has its own test, because shrinking the chat to 240px would satisfy every
other assertion here and be useless.

The Settings tab was measured too and is **not** a bug: it fits at 1200px and
overflows only when its content is genuinely taller than the window.

**Group creation asked one question twice.** Visibility and admission were
separate selectors that could only ever be set together — picking Public reached
over and set the policy — and two of the four combinations are meaningless. The
API already refused public+invite with a 422, so the form could build a request
that could not succeed. Private+open was accepted and should not have been: a
group anyone may join that nobody can find is a listing with the listing
removed, since joining goes through the node and there is no link to pass
around.

So: one selector, "who can join", and the request derives the rest. The API now
refuses the other impossible pair as well, with a message that says which way to
resolve it. Six locale strings the visibility box owned are deleted rather than
left unread in ten files, and the two surviving descriptions now say what each
choice means for who can *find* the group — with the word "public" gone from the
page, nothing else would have said it, and someone would publish a group without
meaning to.

865 tests pass.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

1 files changed, 2 insertions, 8 deletions

diff --git a/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js b/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
index 1ae8217..81b6a3a 100644
--- a/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
+++ b/packages/meshbay-hub/src/meshbay_hub/static/locales/it.js
@@ -321,16 +321,11 @@ export default {
   'create_group.title': 'Crea un gruppo',
   'create_group.name': 'Nome del gruppo',
   'create_group.name_placeholder': 'es. Foto di famiglia, File del progetto...',
-  'create_group.visibility': 'Visibilità',
-  'create_group.private': 'Privato',
-  'create_group.private_desc': 'Solo i membri invitati vedono i file e vi accedono',
-  'create_group.public': 'Pubblico',
-  'create_group.public_desc': 'Chiunque può scoprire e sfogliare questo gruppo',
   'create_group.join_policy': 'Modalità di adesione',
   'create_group.invite': 'Solo su invito',
-  'create_group.invite_desc': 'I membri devono essere invitati da un amministratore',
+  'create_group.invite_desc': "I membri devono essere invitati da un amministratore. Il gruppo non è elencato pubblicamente.",
   'create_group.open': 'Aperto (chiunque può partecipare)',
-  'create_group.open_desc': 'Chiunque può partecipare senza approvazione',
+  'create_group.open_desc': "Elencato tra i gruppi pubblici: chiunque può trovarlo e unirsi senza approvazione.",
   'create_group.description': 'Descrizione',
   'create_group.description_hint': 'Di cosa si occupa questo gruppo? (facoltativo)',
   'create_group.submit': 'Crea',
@@ -450,5 +445,4 @@ export default {
   'group.leave_confirm': 'Uscire da «{name}»? Perderà l’accesso ai suoi file e alla chat. I file che ha caricato restano sul node, e il node mantiene l’identità che ha fissato per lei finché il suo operatore non la rimuove.',
   'profile.title': 'Profilo',
   'usermenu.profile': 'Profilo',
-  'create_group.public_is_open': 'Chiunque può trovare un gruppo pubblico e parteciparvi. Per scegliere chi entra, lo crei privato.',
 };