security(console): mask key-dump command RESULTS in the scrollback

The console redacted secret command ARGS but showed the OUTPUT of key-revealing
commands (dumpprivkey / z_exportkey / z_exportviewingkey / z_exportmnemonic /
dumpwallet / z_exportwallet, and the lite seed/export verbs) in full — visible
in the scrollback, Copy All, Ctrl+C and the filter. Now, when the submitted
command is key-revealing, its result is held ONLY in a member buffer (never in
the scrollback model, so Copy-All etc. can't leak it) and a masked placeholder
is shown. An explicit "Copy secret" button routes through the auto-clearing
clipboard; the buffer auto-wipes after 60s, on Clear, and on wallet lock
(via wipeDisplayedSecrets). The command string passed to the executor is
byte-identical. New pure helper ConsoleCommandRevealsSecret is unit-testable.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/ui/windows/console_tab_helpers.cpp

@@ -71,6 +71,25 @@ bool ConsoleCommandCarriesSecret(const std::string& cmd)
     return false;
 }
 
+bool ConsoleCommandRevealsSecret(const std::string& cmd, bool fullNode)
+{
+    size_t end = 0;
+    const std::string name = firstConsoleTokenLower(cmd, end);
+    if (name.empty()) return false;
+    if (fullNode) {
+        static const char* const kFull[] = {
+            "dumpprivkey", "z_exportkey", "z_exportviewingkey",
+            "z_exportmnemonic", "dumpwallet", "z_exportwallet",
+        };
+        for (const char* s : kFull) if (name == s) return true;
+    } else {
+        // Lite backend verbs whose output is the seed phrase / private keys.
+        static const char* const kLite[] = { "seed", "export" };
+        for (const char* s : kLite) if (name == s) return true;
+    }
+    return false;
+}
+
 std::string RedactConsoleCommand(const std::string& cmd)
 {
     size_t end = 0;