Create persistent runtime Ages

docs/PORTING.md

@@ -190,6 +190,13 @@ generation profile, generation-version marker, canonical name, and creation
 time. The temporary vanilla-dimension adapter remains in place until runtime
 Age dimensions are introduced by a later release slice.
 
+Version 0.2.10.0 makes page-free Descriptive Books playable. Naming an
+unwritten book creates a dedicated, persistent vanilla-like Age through the
+Dynamic Dimensions API. Each Age reloads with its server, retains its terrain,
+and receives a five-by-five cobblestone platform with cleared arrival headroom.
+Non-Nether Ages select the highest sturdy surface near the origin and fall back
+to a platform at Y=63 when no suitable natural footing exists.
+
 The preview code is separated behind a renderer interface and uses an isolated
 Ponder level populated from server-authoritative destination snapshots.