refactor: restore behavior the branch had changed (codex review)

A codex review of the branch found seven places where earlier refactor commits changed behavior. Each is restored here with a test:

- base_service imported flood_scope relatively; the local-service loader also runs that file as local_services.base_service, where the import cannot resolve. Now absolute.
- Radio-health fields were initialized after commands and services were built, so a plugin constructor reading is_radio_offline raised. They are now set before any plugin.
- Removing the per-command can_execute overrides made 31 commands honor skip_channel_check, which their overrides had dropped. BaseCommand.honors_skip_channel_check (False on exactly those commands) keeps them enforcing their channel list.
- CommandManager.get_plugin_metadata, WxCommand.get_weather_for_zipcode and PluginLoader.validate_plugin were public compatibility entry points; they are back.
- feed_manager stopped exporting DEFAULT_MAX_FEED_RESPONSE_BYTES and DEFAULT_MAX_PARSED_FEED_ITEMS despite the commit saying it re-exported them; it does now.
- wx and gwx logged companion-location lookup failures at WARNING; the shared helper logged at debug. It now takes the level.
- The INFO 'MESSAGE ROUTING' / 'DIRECT MESSAGE' lines for pubkey-correlated DMs were removed with the dead path_info computation; they are logged again by a log-only helper.

modules/commands/hello_command.py

@@ -20,6 +20,7 @@ class HelloCommand(BaseCommand):
 
     # Plugin metadata
     name = "hello"
+    honors_skip_channel_check = False
     enabled_attr = "hello_enabled"
     keywords = ['hello', 'hi', 'hey', 'howdy', 'greetings', 'salutations', 'good morning', 'good afternoon', 'good evening', 'good night', 'yo', 'sup', 'whats up', 'what\'s up', 'morning', 'afternoon', 'evening', 'night', 'gday', 'g\'day', 'hola', 'bonjour', 'ciao', 'namaste', 'aloha', 'shalom', 'konnichiwa', 'guten tag', 'buenos dias', 'buenas tardes', 'buenas noches']
     description = "Responds to greetings with robot-themed responses"