fix: publish plugin slash commands in Telegram menu

- discover plugin commands before building Telegram command menus
- make plugin command and context engine accessors lazy-load plugins
- add regression coverage for Telegram menu and plugin lookup paths

tests/hermes_cli/test_commands.py

@@ -688,6 +688,28 @@ class TestTelegramMenuCommands:
                 f"Command '{name}' is {len(name)} chars (limit {_TG_NAME_LIMIT})"
             )
 
+    def test_includes_plugin_commands_via_lazy_discovery(self, tmp_path, monkeypatch):
+        """Telegram menu generation should discover plugin slash commands on first access."""
+        from unittest.mock import patch
+        import hermes_cli.plugins as plugins_mod
+
+        plugin_dir = tmp_path / "plugins" / "cmd-plugin"
+        plugin_dir.mkdir(parents=True, exist_ok=True)
+        (plugin_dir / "plugin.yaml").write_text(
+            "name: cmd-plugin\nversion: 0.1.0\ndescription: Test plugin\n"
+        )
+        (plugin_dir / "__init__.py").write_text(
+            "def register(ctx):\n"
+            "    ctx.register_command('lcm', lambda args: 'ok', description='LCM status and diagnostics')\n"
+        )
+        monkeypatch.setenv("HERMES_HOME", str(tmp_path))
+
+        with patch.object(plugins_mod, "_plugin_manager", None):
+            menu, _ = telegram_menu_commands(max_commands=100)
+
+        menu_names = {name for name, _ in menu}
+        assert "lcm" in menu_names
+
     def test_excludes_telegram_disabled_skills(self, tmp_path, monkeypatch):
         """Skills disabled for telegram should not appear in the menu."""
         from unittest.mock import patch, MagicMock