Find alternate grounded age arrivals

docs/PORTING.md

@@ -159,6 +159,9 @@ animated linking-panel fallback.
 Version 0.2.3 requires Descriptive Book destinations to have a sturdy floor,
 while Linking Books continue to permit passable floorless destinations.
 
+Version 0.2.4 expands Descriptive Book arrival validation with an outward,
+terrain-aware search for an alternate grounded location near an unsafe target.
+
 The preview code is separated behind a renderer interface and uses an isolated
 Ponder level populated from server-authoritative destination snapshots.