fix: accept proofless transfer messages, count them separately

Archives do not persist RLN proofs (no proof column in the message
store schema), so every message served from a peer's archive via
store-sync transfer arrives proofless and was rejected in an endless
retry loop (observed in the simulator: same missing messages
re-transferred and re-rejected every sync round). Validate only
proof-carrying messages; count proofless ones via the new
total_transfer_messages_unverified metric. Real enforcement requires
persisting proofs in the archive - recorded as a production gap.

Part of the "Store as a startup-only dependency" experiment (step 8 fix).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: darshankabariya

logos_delivery/waku/node/waku_node.nim

@@ -404,12 +404,19 @@ proc mountStoreSync*(
     ## RLN mounts after store sync (but before the switch starts accepting
     ## connections), so capture the node and check at call time; nil rln
     ## means RLN is not configured on this network. Freshness is not
-    ## checked: synced messages are old by design. Known gap: proofs built
-    ## against roots older than the acceptable root window are rejected,
-    ## so history sync across heavy membership churn is bounded by it.
+    ## checked: synced messages are old by design. Known gaps: archives do
+    ## not persist RLN proofs, so archive-served messages arrive proofless
+    ## and can only be counted, not verified (enforcement needs proof
+    ## persistence); and proofs built against roots older than the
+    ## acceptable root window are rejected, bounding history sync across
+    ## heavy membership churn.
     if node.rln.isNil():
       return true
 
+    if msg.proof.len == 0:
+      total_transfer_messages_unverified.inc()
+      return true
+
     let res = await node.rln.validateMessage(msg, checkFreshness = false)
     return res == MessageValidationResult.Valid
 

logos_delivery/waku/waku_store_sync.nim

@@ -1,6 +1,9 @@
 {.push raises: [].}
 
 import
-  ./waku_store_sync/reconciliation, ./waku_store_sync/transfer, ./waku_store_sync/common
+  ./waku_store_sync/reconciliation,
+  ./waku_store_sync/transfer,
+  ./waku_store_sync/common,
+  ./waku_store_sync/protocols_metrics
 
-export reconciliation, transfer, common
+export reconciliation, transfer, common, protocols_metrics

logos_delivery/waku/waku_store_sync/protocols_metrics.nim

@@ -20,6 +20,9 @@ declarePublicCounter total_bytes_exchanged,
 declarePublicCounter total_transfer_messages_rejected,
   "number of received transfer messages dropped by validation"
 
+declarePublicCounter total_transfer_messages_unverified,
+  "number of received transfer messages accepted without proof verification (archives do not persist RLN proofs)"
+
 declarePublicCounter total_transfer_messages_exchanged,
   "the number of messages sent and received by the transfer protocol", ["direction"]