Add hbd/server/oauth.py with OAuthError, _gitea_cfg(), and is_enabled()
to detect when all three required Gitea OAuth2 config keys are present.
Add "oauth": {} default to SERVER_DEFAULTS in config.py.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
When NagiosRunnerPlugin has no commands configured, set skip_reason before
returning False from initialize(). This allows PluginLoader to log INFO
(not WARNING) when the plugin is skipped.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>