core: preserve domain during group handshake

src/Simplex/Chat/Store/Groups.hs

@@ -2721,7 +2721,11 @@ updateGroupProfile db user@User {userId} g@GroupInfo {groupId, localDisplayName,
     -- group_domain is owned by publicGroup; when the incoming profile has no publicGroup (a business, whose domain
     -- is set out-of-band) the CASE leaves the stored group_domain unchanged instead of clearing it.
     updateGroupProfile_ currentTs =
-      let (groupWebPage_, groupDomain_, domainWebPage_, allowEmbedding_, groupDomainProof_) = publicGroupAccessRow publicGroup
+      -- the wire carries the domain but not its signed proof (the group's link is authoritative for the claim), so
+      -- keep the stored proof on an unchanged domain instead of overwriting it with the empty incoming one, the same
+      -- way updateContactProfile preserves contactDomain's proof
+      let (groupWebPage_, groupDomain_, domainWebPage_, allowEmbedding_, _) = publicGroupAccessRow publicGroup
+          groupDomainProof_ = if claimChanged then Nothing else oldPublicGroup >>= publicGroupAccess >>= groupDomainClaim >>= proof
        in DB.execute
             db
             [sql|

src/Simplex/Chat/View.hs

@@ -1827,10 +1827,12 @@ viewContactInfo ct@Contact {contactId, profile = LocalProfile {localAlias, conta
     <> viewCustomData customData
 
 viewGroupInfo :: GroupInfo -> [StyledString]
-viewGroupInfo gInfo@GroupInfo {groupId, uiThemes, customData, groupSummary = GroupSummary {currentMembers, publicMemberCount}} =
+viewGroupInfo gInfo@GroupInfo {groupId, businessChat, groupDomainVerified, uiThemes, customData, groupSummary = GroupSummary {currentMembers, publicMemberCount}} =
   [ "group ID: " <> sShow groupId,
     memberCountLine
   ]
+    -- a business presents as a contact, so its verified domain is shown as an @-name
+    <> simplexDomainLine NTContact (businessDomain =<< businessChat) groupDomainVerified
     <> viewUITheme uiThemes
     <> viewCustomData customData
   where

tests/ChatTests/Names.hs

@@ -239,5 +239,10 @@ testConnectByNameBusinessAndChannel ps = withSmpServerAndNames $ \reg ->
         bob ##> "/_connect plan 1 @biz.simplex resolve=never"
         bob <## "business address: known business #alice"
         bob <## "use #alice <message> to send messages"
+        -- the business's verified domain survives the handshake and is shown in group info
+        bob ##> "/i #alice"
+        bob <## "group ID: 1"
+        bob <## "current members: 2"
+        bob <## "SimpleX name: @biz.simplex (verified)"
   where
     bizName = SimplexNameInfo NTContact (SimplexDomain TLDSimplex "biz" [])