feat: register title, resume, and other missing commands with platform menus

Add /title, /resume, /compress, /provider, /usage to Telegram's
set_my_commands so they appear in the / autocomplete menu.

Add /title, /resume, /compress, /provider, /usage, /help as Discord
slash commands so they appear in Discord's native command picker.

These commands were functional via text but not registered with the
platform-native command menus, so users couldn't discover them.

gateway/platforms/telegram.py

@@ -155,6 +155,11 @@ class TelegramAdapter(BasePlatformAdapter):
                     BotCommand("status", "Show session info"),
                     BotCommand("stop", "Stop the running agent"),
                     BotCommand("sethome", "Set this chat as the home channel"),
+                    BotCommand("compress", "Compress conversation context"),
+                    BotCommand("title", "Set or show the session title"),
+                    BotCommand("resume", "Resume a previously-named session"),
+                    BotCommand("usage", "Show token usage for this session"),
+                    BotCommand("provider", "Show available providers"),
                     BotCommand("help", "Show available commands"),
                 ])
             except Exception as e: