Accept plain 'exit'/'quit' in MCP chat

Update Rakefile conversational CLI to recognize plain "exit" and "quit" as commands to leave the chat. Also update help text to list these aliases. This makes the MCP chat interface more forgiving of common exit commands.

Author: AdrianCurtin

Rakefile

@@ -364,7 +364,7 @@ namespace :mcp do
   #   /trace   — toggle tool-call tracing on/off
   #   /cost    — show running token + USD cost totals
   #   /history — print conversation history
-  #   /exit    — leave the chat (also: /quit, Ctrl-D, empty line)
+  #   /exit    — leave the chat (also: /quit, exit, quit, Ctrl-D, empty line)
   # -------------------------------------------------------------------------
   desc "Conversational CLI: talk to your Parse data via the MCP agent"
   task :chat do
@@ -404,7 +404,7 @@ namespace :mcp do
       puts "  /trace   — toggle per-turn tool-call tracing on/off"
       puts "  /cost    — show running token + USD totals (and last turn)"
       puts "  /history — print the conversation log"
-      puts "  /exit    — leave (also /quit, Ctrl-D, empty line)"
+      puts "  /exit    — leave (also /quit, exit, quit, Ctrl-D, empty line)"
     end
 
     puts "=" * 70
@@ -421,7 +421,7 @@ namespace :mcp do
       next if line.empty?
 
       case line
-      when "/exit", "/quit"
+      when "/exit", "/quit", "exit", "quit"
         break
       when "/help"
         slash_help.call