fix(gateway,discord-plugin): _platform_status must respect is_connected=False, not silently fall back to check_fn

Two bugs surfaced by PR #24356 migrating Discord into the registry:

1. plugins/platforms/discord/adapter.py::_is_connected — read DISCORD_BOT_TOKEN
   via hermes_cli.gateway.get_env_value (the abstraction tests patch) instead
   of os.getenv directly. The legacy non-registry path used get_env_value;
   bypassing it broke test_setup_openclaw_migration which patches
   gateway_mod.get_env_value to simulate a hermetic env.

2. hermes_cli/gateway.py::_platform_status — when entry.is_connected is
   defined and returns False, return 'not configured' immediately. Don't
   fall back to entry.check_fn(), which would let 'SDK is installed'
   override 'no token configured' and incorrectly report the platform as
   ready. The fallback to check_fn is the right behaviour only when
   is_connected is None (not registered).

Fixes 5 test failures observed on CI for PR #24356:
- tests/hermes_cli/test_setup.py::test_setup_gateway_skips_service_install_when_systemctl_missing
- tests/hermes_cli/test_setup.py::test_setup_gateway_in_container_shows_docker_guidance
- tests/hermes_cli/test_setup_irc.py::TestIRCGatewaySetupFreshInstall::test_setup_gateway_irc_counts_as_messaging_platform
- tests/hermes_cli/test_setup_openclaw_migration.py::TestGetSectionConfigSummary::test_gateway_returns_none_without_tokens
- tests/hermes_cli/test_setup_openclaw_migration.py::TestSetupWizardSkipsConfiguredSections::test_sections_skipped_when_migration_imported_settings

Same _platform_status bug exists for sibling plugin platforms (teams,
google_chat) whose check_fn returns true on SDK install alone; their
tests just never exercised the registry path before. The bug only became
test-visible when Discord migrated into the registry.

Validation: 11,167 tests across tests/gateway/ + tests/cron/ +
tests/tools/test_send_message_tool.py + tests/hermes_cli/ pass with zero
failures.

hermes_cli/gateway.py

@@ -3737,7 +3737,12 @@ def _platform_status(platform: dict) -> str:
                 configured = bool(entry.is_connected(synthetic))
             except Exception:
                 configured = False
-        if not configured:
+        else:
+            # No is_connected hook — fall back to check_fn as a coarse
+            # "are deps present" gate. Don't fall back when is_connected
+            # is defined and returned False; that would let "SDK is
+            # installed" override "no token configured" and incorrectly
+            # report the platform as ready.
             try:
                 configured = bool(entry.check_fn())
             except Exception:

plugins/platforms/discord/adapter.py

@@ -6137,9 +6137,16 @@ def _apply_yaml_config(yaml_cfg: dict, discord_cfg: dict) -> dict | None:
 
 
 def _is_connected(config) -> bool:
-    """Discord is considered connected when DISCORD_BOT_TOKEN is set."""
-    import os
-    return bool(os.getenv("DISCORD_BOT_TOKEN", "").strip())
+    """Discord is considered connected when DISCORD_BOT_TOKEN is set.
+
+    Looks up via ``hermes_cli.gateway.get_env_value`` at call time (not via
+    the plugin's own bound import) so tests that patch ``gateway_mod.get_env_value``
+    — including ``test_setup_openclaw_migration`` — can suppress ambient
+    ``DISCORD_BOT_TOKEN`` env vars. Matches what the legacy
+    ``_PLATFORMS["discord"]`` dispatch did before this migration.
+    """
+    import hermes_cli.gateway as gateway_mod
+    return bool((gateway_mod.get_env_value("DISCORD_BOT_TOKEN") or "").strip())
 
 
 def _build_adapter(config):