fix(ecstore): guard free-version decommission conflicts

crates/filemeta/src/filemeta.rs

@@ -462,6 +462,10 @@ impl FileMeta {
         };
 
         if let Some(fidx) = existing_idx {
+            let existing = self.versions[fidx].parse_version_meta()?;
+            if existing.free_version() != version.free_version() {
+                return Err(Error::other("cannot replace a free version with a non-free version"));
+            }
             return self.set_idx(fidx, version);
         }