The portal's `SettingsModal` was a parallel, mock-backed settings
implementation. It's replaced by the editor's `AppConfigModal`, mounted
via a new `PortalSettingsHost` that supplies the contexts the portal
doesn't have (app config, flavor-resolved session, preferences, editor
theme). Flavor resolution does the rest: the self-hosted portal gets the
admin sections, the SaaS portal gets the saas shell. The self-hosted
account-link panel rides in through the existing seam as an extra
section.
The shell gains three host props (`urlSync`, `initialSection`,
`extraSections`); editor behaviour is unchanged. Net −1,300 lines.
Manually verified on both flavors against live backends.
