Add real authentication to ConsoleServer/ConsoleSession, fix CommandList help

ConsoleSession's login flow never actually checked anything: the
entered username was discarded and the password was never compared,
so any input (including blank) reached the command prompt. Confirmed
live via an unauthenticated login against BARANTMail's admin console
on port 1027, which was reachable externally. ConsoleServer now takes
an optional credentialChecker callback consulted by the WAIT_PASSWORD
state; omitting it preserves the old accept-anything behavior for any
other use of this class.

Separately, the console never prompted until the client's first line
arrived - that line was silently discarded just to kick the state
machine off, shifting every subsequent line one slot early. Harmless
under the old accept-anything login, but it broke real credential
checking outright (the typed password was compared against the typed
username, etc). ConsoleSession::onConnected() now starts the state
machine immediately on connect instead.

CommandList::processCommand() was a no-op stub - the intended
"typing help lists the registered commands" body was commented out,
and even referenced a Command::getName() that was never added to the
base class. The map's own key from add() already is the registered
name, so this just walks it directly.

ConsoleSession.h

@@ -16,6 +16,14 @@ namespace core {
    /// Extend the protocol() method in order to define the behavior and
    /// protocol interaction for this socket which is a console session.
    ///
+   /// The User:/Password: exchange is a real login when the owning
+   /// ConsoleServer was constructed with a credentialChecker (see its
+   /// own doc comment) - previously the entered username was never
+   /// even stored and the password was never compared against
+   /// anything, so any input (including blank) reached the command
+   /// prompt. A ConsoleServer built without a credentialChecker still
+   /// accepts anything, matching that original behavior exactly.
+   ///
 
    class ConsoleSession : public TerminalSession {
 
@@ -28,11 +36,27 @@ namespace core {
     protected:
       void protocol(coreutils::ZString &data) override;
 
+      // Previously absent entirely, so the state machine only ever
+      // advanced on the CLIENT's first line of input - that line was
+      // consumed just to drive WELCOME->LOGIN and was never used as
+      // real content, meaning every subsequent line was shifted one
+      // slot early (what the user typed as their *username* actually
+      // got compared as nothing, their *password* got captured as
+      // enteredUser, and their first real command got compared as the
+      // password). Harmless before real credential checking existed -
+      // any input reached the prompt regardless - but it broke login
+      // outright once checkCredentials() started actually comparing
+      // values. Kicking the state machine off here instead means
+      // "User: " is sent immediately on connect, before the client
+      // has sent anything at all.
+      void onConnected() override;
+
     private:
       enum Status {WELCOME, LOGIN, WAIT_USER_PROFILE, PASSWORD, WAIT_PASSWORD, PROMPT, INPUT, PROCESS, DONE};
       Status status = WELCOME;
       void doCommand(coreutils::ZString &request);
       coreutils::ZString command;
+      std::string enteredUser;
 
    };