refactor WalletSeed type, see mq wip

src/Simplex/Chat/Store/SQLite/Migrations/chat_schema.sql

@@ -984,6 +984,7 @@ CREATE TABLE badge_code_redemptions(
 CREATE TABLE wallet_seeds(
   wallet_seed_id INTEGER PRIMARY KEY AUTOINCREMENT,
   entropy BLOB NOT NULL CHECK(length(entropy) = 32),
+  master BLOB NOT NULL CHECK(length(master) = 64),
   next_account_index INTEGER CHECK(next_account_index BETWEEN 0 AND 2147483648),
   single_seed INTEGER NOT NULL DEFAULT 1
 ) STRICT;