Keep source plugins in single scraper process

docs/architecture.md

@@ -17,6 +17,7 @@ Related documents:
 - [settings-navigation.md](settings-navigation.md): User/Admin workspace, scraper tabs and deep links.
 - [peering.md](peering.md): optional private server-to-server catalog and transfer.
 - [discovery.md](discovery.md): reader-owned, opt-in deterministic discovery feed and its limits.
+- [source-modules.md](source-modules.md): adding and maintaining first-party hosters inside the single scraper process.
 
 ## 1. Principles