feat: add /profile slash command to show active profile (#4027)

Adds /profile to COMMAND_REGISTRY (Info category) with handlers in
both CLI and gateway. Shows the active profile name and home directory.

Works on all platforms — CLI, Telegram, Discord, Slack, etc.
Detects profile by checking if HERMES_HOME is under ~/.hermes/profiles/.
Shows 'default' when running without a profile.

hermes_cli/commands.py

@@ -71,6 +71,7 @@ COMMAND_REGISTRY: list[CommandDef] = [
                aliases=("q",), args_hint="<prompt>"),
     CommandDef("status", "Show session info", "Session",
                gateway_only=True),
+    CommandDef("profile", "Show active profile name and home directory", "Info"),
     CommandDef("sethome", "Set this chat as the home channel", "Session",
                gateway_only=True, aliases=("set-home",)),
     CommandDef("resume", "Resume a previously-named session", "Session",