feat(plugins): add enable/disable commands + interactive toggle UI (#3747)

Adds plugin management with three interfaces:

  hermes plugins          # interactive curses checklist (like hermes tools)
  hermes plugins enable   # non-interactive enable
  hermes plugins disable  # non-interactive disable
  hermes plugins list     # table with status column

Disabled plugins are stored in config.yaml under plugins.disabled and
skipped during discovery. Uses the same curses_checklist component as
hermes tools for the interactive UI.

Changes:
- hermes_cli/plugins.py: _get_disabled_plugins() + skip disabled during
  discover_and_load()
- hermes_cli/plugins_cmd.py: cmd_toggle() interactive UI, cmd_enable(),
  cmd_disable(), updated cmd_list() with status column
- hermes_cli/main.py: enable/disable subparser entries
- website/docs/reference/cli-commands.md: updated plugins section
- website/docs/user-guide/features/plugins.md: updated managing section

hermes_cli/main.py

@@ -3779,6 +3779,16 @@ For more help on a command:
 
     plugins_subparsers.add_parser("list", aliases=["ls"], help="List installed plugins")
 
+    plugins_enable = plugins_subparsers.add_parser(
+        "enable", help="Enable a disabled plugin"
+    )
+    plugins_enable.add_argument("name", help="Plugin name to enable")
+
+    plugins_disable = plugins_subparsers.add_parser(
+        "disable", help="Disable a plugin without removing it"
+    )
+    plugins_disable.add_argument("name", help="Plugin name to disable")
+
     def cmd_plugins(args):
         from hermes_cli.plugins_cmd import plugins_command
         plugins_command(args)