fix: isolate per-chain mapping failures in currentChains, not just register/unregister

mapChainLocalToChain() runs as a single mapList{} transform over the entire
chain list. If it throws for even one malformed row (e.g. a JSON parse
failure on the chain's `additional` blob), the whole transform throws,
killing the Eagerly-shared currentChains/chainsById flows for every chain -
permanently, since Eagerly sharing never restarts once its upstream dies.

This is the same class of bug already fixed for registerChain/unregisterChain
in the diff-processing step below, but one level upstream of it: a mapping
failure here never even reaches that per-chain isolation, since it happens
before the diff is computed at all.

Device logs on a fresh install showed exactly this shape: 8 chains (including
Pezkuwi, Pezkuwi Asset Hub, Polkadot Asset Hub) successfully completed
"Constructed runtime" within the first ~2.5 seconds, then all activity for
every remaining chain stopped completely for the rest of the session - no
crash, no battery-saver kill (confirmed off), the process simply went silent,
consistent with the shared flow dying mid-registration and never recovering.

runtime/src/main/java/io/novafoundation/nova/runtime/multiNetwork/ChainRegistry.kt

@@ -7,7 +7,7 @@ import io.novafoundation.nova.common.utils.RuntimeContext
 import io.novafoundation.nova.common.utils.diffed
 import io.novafoundation.nova.common.utils.filterList
 import io.novafoundation.nova.common.utils.inBackground
-import io.novafoundation.nova.common.utils.mapList
+import io.novafoundation.nova.common.utils.mapListNotNull
 import io.novafoundation.nova.common.utils.mapNotNullToSet
 import io.novafoundation.nova.common.utils.provideContext
 import io.novafoundation.nova.common.utils.removeHexPrefix
@@ -75,7 +75,16 @@ class ChainRegistry(
 ) : CoroutineScope by CoroutineScope(SupervisorJob() + Dispatchers.Default) {
 
     val currentChains = chainDao.joinChainInfoFlow()
-        .mapList { mapChainLocalToChain(it, gson) }
+        // mapListNotNull, not mapList: mapChainLocalToChain() can throw on a single malformed row (e.g. a
+        // gson.fromJson() failure on the chain's `additional` JSON blob) - since this whole step runs as ONE
+        // transform over the ENTIRE chain list, one bad chain would previously throw out of this operator and
+        // permanently kill this Eagerly-shared flow for every chain, not just the offending one. Skip and log
+        // instead, matching the per-chain isolation already applied to registerChain/unregisterChain below.
+        .mapListNotNull { chainLocal ->
+            runCatching { mapChainLocalToChain(chainLocal, gson) }
+                .onFailure { Log.e(LOG_TAG, "Failed to map chain ${chainLocal.chain.id} (${chainLocal.chain.name}) from local DB", it) }
+                .getOrNull()
+        }
         .diffed()
         .map { diff ->
             // Each chain's register/unregister is isolated: one malformed/leftover row (e.g. a chain persisted