gui/wallet: name backups by backend, and stop saying "wallet.dat" for phrase gaps

Two things that read wrong once the wallet is on SQLite:

- The Wallet Safety backup dialog defaulted the file name to .dat, but
  BackupWallet copies wallet.sqlite under the SQLite backend -- so the
  suggested name put SQLite contents in a wallet-backup-*.dat file. The
  default now matches the live backend (.sqlite on SQLite, .dat on BDB).

- The recovery audit called coins on non-phrase keys "wallet.dat-only" and
  told the user to "keep wallet.dat backups". Under SQLite those coins live
  in wallet.sqlite, not wallet.dat. Reworded to the backend-neutral truth:
  "not phrase-backed" balance, and "keep a file backup of this wallet" --
  accurate on either backend. Same wording in the CLI -recoveryaudit and
  the GUI Wallet Safety panel.

Display/naming only; audit numbers and BackupWallet are unchanged. All 13
wallet suites still pass.

2 files changed, 12 insertions, 8 deletions

diff --git a/src/gui.cpp b/src/gui.cpp
index 81dd8e0..672f0ff 100644
--- a/src/gui.cpp
+++ b/src/gui.cpp
@@ -175,7 +175,11 @@ static bool PathIsInsideDataDir(const std::string& strPath)
 
 static void SetDefaultBackupPath()
 {
-    std::string path = DefaultBackupDir() + "/wallet-backup-" + BackupTimeSuffix() + ".dat";
+    // Match the extension to the live backend: BackupWallet copies wallet.sqlite
+    // under the SQLite backend and wallet.dat under Berkeley DB, so a ".dat"
+    // default name would put SQLite contents in a misleadingly-named file.
+    const char* pszExt = WalletSQLiteRuntimeActive() ? ".sqlite" : ".dat";
+    std::string path = DefaultBackupDir() + "/wallet-backup-" + BackupTimeSuffix() + pszExt;
     strncpy(g_backupPath, path.c_str(), sizeof(g_backupPath)-1);
     g_backupPath[sizeof(g_backupPath)-1] = '\0';
 }
@@ -1257,11 +1261,11 @@ static void DrawWalletSafetyDialog()
         }
         ImGui::Text("Phrase-backed spendable balance: %s BTF",
                     FmtMoney(g_recoveryAudit.nRecoverableCredit).c_str());
-        ImGui::Text("Wallet.dat-only spendable balance: %s BTF",
+        ImGui::Text("Not phrase-backed spendable balance: %s BTF",
                     FmtMoney(g_recoveryAudit.nLegacyCredit).c_str());
         ImGui::Text("Phrase-backed immature mining rewards: %s BTF",
                     FmtMoney(g_recoveryAudit.nRecoverableImmatureCredit).c_str());
-        ImGui::Text("Wallet.dat-only immature mining rewards: %s BTF",
+        ImGui::Text("Not phrase-backed immature mining rewards: %s BTF",
                     FmtMoney(g_recoveryAudit.nLegacyImmatureCredit).c_str());
         if (!g_recoveryAudit.fDeriveComplete)
         {
@@ -1275,8 +1279,8 @@ static void DrawWalletSafetyDialog()
             ImGui::PushStyleColor(ImGuiCol_Text, ImVec4(1.0f, 0.75f, 0.25f, 1.0f));
             ImGui::TextWrapped(
                 "Some coins are on keys the phrase does not reproduce. "
-                "Keep wallet.dat backups until that balance has been moved to a "
-                "phrase-backed address.");
+                "Keep a file backup of this wallet until that balance has been "
+                "moved to a phrase-backed address.");
             ImGui::PopStyleColor();
         }
         else if (HaveHDSeed() &&
diff --git a/src/walletcmd.cpp b/src/walletcmd.cpp
index 1f1fd27..f59fc0c 100644
--- a/src/walletcmd.cpp
+++ b/src/walletcmd.cpp
@@ -429,13 +429,13 @@ int CmdRecoveryAudit()
     }
     printf("  covered by recovery phrase:   %s BTF (%d transaction(s))\n",
            FormatMoney(audit.nRecoverableCredit).c_str(), audit.nRecoverableTx);
-    printf("  wallet.dat-only balance:      %s BTF (%d transaction(s))\n",
+    printf("  not phrase-backed balance:    %s BTF (%d transaction(s))\n",
            FormatMoney(audit.nLegacyCredit).c_str(), audit.nLegacyTx);
     printf("  immature mining rewards:      %s BTF\n", FormatMoney(nImmatureTotal).c_str());
     printf("    phrase-backed immature:     %s BTF (%d transaction(s))\n",
            FormatMoney(audit.nRecoverableImmatureCredit).c_str(),
            audit.nRecoverableImmatureTx);
-    printf("    wallet.dat-only immature:   %s BTF (%d transaction(s))\n",
+    printf("    not phrase-backed immature: %s BTF (%d transaction(s))\n",
            FormatMoney(audit.nLegacyImmatureCredit).c_str(),
            audit.nLegacyImmatureTx);
 
@@ -457,7 +457,7 @@ int CmdRecoveryAudit()
     {
         printf("\n");
         printf("Warning: some coins are on keys the phrase does not reproduce.\n");
-        printf("Keep wallet.dat backups until that balance has been moved to a phrase-backed address.\n");
+        printf("Keep a file backup of this wallet until that balance has been moved to a phrase-backed address.\n");
         fflush(stdout);
         return 2;
     }