chat: CESimplexNameUnprepared for found-but-no-link cases + member-removed filter

connectPlanName previously threw CEInvalidConnReq when a name lookup
hit a contact / group row whose preparedContact / preparedGroup was
NULL. The error message ("Connection link is invalid, possibly it was
created in a previous version") was wrong: the name resolved fine,
the device just has no link material to reconnect via (typical for a
contact created via the XInfo handler rather than the prepare path).
Introduce CESimplexNameUnprepared SimplexNameInfo for this case.

Also mirror the link-based path's gPlan (Commands.hs:4133) for groups
whose membership state is GSMemRemoved — return CESimplexNameNotFound
rather than GLPKnown for a removed-member group, since GLPKnown for
removed members would be inconsistent with how /_connect plan over a
short link handles the same situation.

src/Simplex/Chat/Controller.hs

@@ -1369,6 +1369,7 @@ data ChatErrorType
   | CEChatStoreChanged
   | CEInvalidConnReq
   | CESimplexNameNotFound {simplexName :: SimplexNameInfo}
+  | CESimplexNameUnprepared {simplexName :: SimplexNameInfo}
   | CEUnsupportedConnReq
   | CEInvalidChatMessage {connection :: Connection, msgMeta :: Maybe MsgMetaJSON, messageData :: Text, message :: String}
   | CEConnReqMessageProhibited

src/Simplex/Chat/Library/Commands.hs

@@ -4181,15 +4181,20 @@ processChatCommand vr nm = \case
         case ct_ of
           Just ct -> case preparedContact ct of
             Just PreparedContact {connLinkToConnect} -> pure (connLinkToConnect, CPContactAddress (CAPKnown ct))
-            Nothing -> throwChatError CEInvalidConnReq
+            -- Row exists but carries no reconnect link (e.g. created via XInfo, not via prepare).
+            -- The name resolves; the device just lacks the connection material to re-establish.
+            Nothing -> throwChatError $ CESimplexNameUnprepared ni
           Nothing -> throwChatError $ CESimplexNameNotFound ni
       NTPublicGroup -> do
         g_ <- withFastStore $ \db -> getGroupInfoBySimplexName db vr user ni
         case g_ of
+          -- Mirror gPlan at line ~4133 in the link-based path: a removed member is not a
+          -- known-and-reconnectable group; treat as "not found" so the caller can try elsewhere.
+          Just g | memberRemoved (membership g) -> throwChatError $ CESimplexNameNotFound ni
           Just g -> case preparedGroup g of
             Just PreparedGroup {connLinkToConnect = ccLink} ->
               pure (ACCL SCMContact ccLink, CPGroupLink (GLPKnown g (BoolDef False) Nothing (ListDef [])))
-            Nothing -> throwChatError CEInvalidConnReq
+            Nothing -> throwChatError $ CESimplexNameUnprepared ni
           Nothing -> throwChatError $ CESimplexNameNotFound ni
     connectWithPlan :: User -> IncognitoEnabled -> ACreatedConnLink -> ConnectionPlan -> CM ChatResponse
     connectWithPlan user@User {userId} incognito ccLink plan

src/Simplex/Chat/View.hs

@@ -2626,6 +2626,7 @@ viewChatError isCmd logLevel testView = \case
     CEChatStoreChanged -> ["error: chat store changed, please restart chat"]
     CEInvalidConnReq -> viewInvalidConnReq
     CESimplexNameNotFound ni -> ["no contact or group with simplex name " <> plain (T.unpack (shortNameInfoStr ni))]
+    CESimplexNameUnprepared ni -> [plain (T.unpack (shortNameInfoStr ni)) <> " is a known contact/group but has no link to reconnect via"]
     CEUnsupportedConnReq -> [ "", "Connection link is not supported by the your app version, please ugrade it.", plain updateStr]
     CEInvalidChatMessage Connection {connId} msgMeta_ msg e ->
       [ plain $