chat: persist peer-claimed simplexName from incoming profiles

Write paths:
- updateContactProfile_' / updateGroupProfile_ now set the new
  contact_profiles.simplex_name / group_profiles.simplex_name columns
  from Profile.simplexName / GroupProfile.simplexName respectively.
- createContact_ INSERT writes Profile.simplexName to the new
  contact_profiles column (separate from the existing simplexName arg,
  which still writes contacts.simplex_name — the user's locally-known
  label).

Read paths (closing Task 2's deferred sites):
- toContact splits simplex_name reads: Contact.simplexName from
  contacts.simplex_name (existing); LocalProfile.simplexName from
  contact_profiles.simplex_name (new column).
- toGroupInfo similarly splits: GroupInfo.simplexName from
  groups.simplex_name; groupProfile.simplexName from
  group_profiles.simplex_name.
- ProfileRow / rowToLocalProfile, toContactRequest, getUserContactProfiles,
  toGroupProfile, getProfileById, groupMemberQuery, getGroupAndMember_,
  saveRcvChatItem-related quotes — all extended to read p.simplex_name
  and decode it into LocalProfile.simplexName / GroupProfile.simplexName.

Conflict handling (Decision B):
- clearConflictingContactProfileSimplexName_ / *Group* helpers do an
  atomic UPDATE-with-RETURNING that NULLs simplex_name on any other
  row in the same user that would collide on the partial UNIQUE index,
  returning the displaced row's display_name.
- updateContactProfileWithConflict / updateGroupProfileWithConflict
  bundle clear+update in one transaction.
- processContactProfileUpdate / xGrpInfo invoke the *WithConflict
  variants and emit CEvtSimplexNameConflict when a displacement
  happened (with the claiming and displaced display names).

Adds ChatEvent CEvtSimplexNameConflict and SimplexNameConflictEntity
(SNCEContact / SNCEGroup) with JSON instances and View.hs rendering.

src/Simplex/Chat/Controller.hs

@@ -946,6 +946,15 @@ data ChatEvent
   | CEvtTimedAction {action :: String, durationMilliseconds :: Int64}
   | CEvtTerminalEvent TerminalEvent
   | CEvtCustomChatEvent {user_ :: Maybe User, response :: Text}
+  | -- Emitted when an incoming peer Profile / GroupProfile carrying a
+    -- simplexName collides with another row in the same user's DB that
+    -- already holds that name. The older row's simplex_name is NULLed
+    -- (newer-claim-wins per RSLV); displacedFrom is the old row's local
+    -- display_name, claimedBy is the peer / group whose claim won.
+    CEvtSimplexNameConflict {user :: User, simplexName :: SimplexNameInfo, entity :: SimplexNameConflictEntity, claimedBy :: ContactName, displacedFrom :: ContactName}
+  deriving (Show)
+
+data SimplexNameConflictEntity = SNCEContact | SNCEGroup
   deriving (Show)
 
 data TerminalEvent
@@ -1771,6 +1780,8 @@ $(JQ.deriveJSON defaultJSON ''RelayTestFailure)
 
 $(JQ.deriveJSON (sumTypeJSON $ dropPrefix "CR") ''ChatResponse)
 
+$(JQ.deriveJSON (enumJSON $ dropPrefix "SNCE") ''SimplexNameConflictEntity)
+
 $(JQ.deriveJSON (sumTypeJSON $ dropPrefix "CEvt") ''ChatEvent)
 
 $(JQ.deriveFromJSON defaultJSON ''ArchiveConfig)