Complete Milestone 3 documentation (#12)

README.md

@@ -4,10 +4,10 @@ Rivencraft is a clean, incremental port of the ideas and gameplay of
 [Mystcraft Legacy](https://github.com/Mystcraft/Mystcraft-Legacy) to Minecraft
 1.21.1 on NeoForge.
 
-The bootstrap and books/linking milestones are complete. The project currently
-provides functional Linking Books and randomly seeded, persistent vanilla-like
-Ages created from page-free Descriptive Books. Symbols, instability, and the
-full writing mechanics have not been ported yet.
+The bootstrap, books/linking, and Ages milestones are complete. The project
+currently provides functional Linking Books and randomly seeded, persistent
+vanilla-like Ages created from page-free Descriptive Books. Symbols,
+instability, and the full writing mechanics have not been ported yet.
 
 ## Linking Book
 
@@ -60,6 +60,10 @@ according to the configured Return Link policy.
 
 Server owners can set `descriptive_books.return_link_mode` in Rivencraft's
 server config to `ON_CREATION` (default), `ALWAYS`, or `DISABLED`.
+Age creation, persistence, lifecycle commands, configuration, backups, and
+administrator recovery are documented in [docs/AGES.md](docs/AGES.md).
+Data-pack runtime profiles are documented in
+[docs/AGE_PROFILES.md](docs/AGE_PROFILES.md).
 
 ## Requirements