sim+chain: strict mix-pool readiness gate + bump nwaku for RLN race work

simulations/mix_lez_chat/run_simulation.sh:
- Strict mix-pool readiness wait: now requires NUM_NODES-1 client
  registrations succeeded on the gifter (one per non-gifter mix node)
  AND a "Gifter self-registered as mix relay" log line on node0 —
  not just GR>=3 which could pass while node0 itself hadn't yet
  finished its own membership flow. Lets every mix node actually be
  ready to generate forward proofs before sender starts.
- Bumps testnet KADEMLIA_HARD_CAP to 1800s (30 min). Testnet block
  times + finality lag put 4 sequential mix-node registrations well
  beyond the old 600s ceiling.

vendor/nwaku bump pulls in:
- unified get_merkle_proofs that returns valid_roots atomically;
- self-verify in spam_protection.generateProof;
- ExternalMerkleProof.validRoots field + pollLoop refresh from it;
- proofRoot/getPollInterval accessors on OnchainLEZGroupManager;
- confirmMembershipLeafIndex helper (unused — wiring foundation for a
  follow-up background watcher to close the slot-allocation race).

simulations/mix_lez_chat/run_simulation.sh

@@ -95,7 +95,9 @@ esac
 # Timing floors: local sequencer ~15s blocks vs testnet ~60s + more variance.
 if [ "$SIM_NETWORK" = testnet ]; then
     KADEMLIA_MIN_WAIT=${SIM_KADEMLIA_MIN_WAIT:-120}
-    KADEMLIA_HARD_CAP=${SIM_KADEMLIA_HARD_CAP:-600}
+    # Testnet block times + finality lag can stretch RLN tx confirmations to
+    # multiple minutes per mix node. 4 nodes × ~5 min each + slack ≈ 30 min.
+    KADEMLIA_HARD_CAP=${SIM_KADEMLIA_HARD_CAP:-1800}
     RECEIVER_MIN_WAIT=${SIM_RECEIVER_MIN_WAIT:-60}
     DELIVERY_TIMEOUT=${SIM_DELIVERY_TIMEOUT:-300}
     NODE_STARTUP_SLEEP=${SIM_NODE_STARTUP_SLEEP:-30}
@@ -433,9 +435,18 @@ done
 # the kad-peer count is logged only for diagnostics.
 echo "  Waiting for kademlia propagation + RLN convergence..."
 KADEMLIA_T0=$SECONDS
+# Mix circuits drop sphinx packets at any hop whose RLN credentials aren't
+# yet confirmed on-chain (Plugin not ready). Wait for ALL mix nodes to be
+# fully registered before starting chat:
+#   - node0 (gifter) self-registers — logs "Gifter self-registered as mix relay"
+#   - node1..N-1 each register via gifter — node0 logs "RLN gifter
+#     registration succeeded" once per client.
+# Required: 1 self-reg + (NUM_NODES - 1) client regs.
+REQUIRED_CLIENT_REGS=$((NUM_NODES - 1))
 while true; do
     ELAPSED=$((SECONDS - KADEMLIA_T0))
     GR=$(sed 's/\x1b\[[0-9;]*m//g' "$STATE_DIR/node0.log" 2>/dev/null | grep -c "RLN gifter registration succeeded" || true); GR=${GR:-0}
+    SELF=$(sed 's/\x1b\[[0-9;]*m//g' "$STATE_DIR/node0.log" 2>/dev/null | grep -c "Gifter self-registered as mix relay" || true); SELF=${SELF:-0}
     LR=0
     MIX_PEERS_PER_NODE=""
     for i in $(seq 0 $((NUM_NODES - 1))); do
@@ -445,11 +456,11 @@ while true; do
         MP=$(sed 's/\x1b\[[0-9;]*m//g' "$LOG" 2>/dev/null | grep -c "mix peer added via kademlia lookup" || true); MP=${MP:-0}
         MIX_PEERS_PER_NODE="${MIX_PEERS_PER_NODE}n${i}=${MP} "
     done
-    if [ "$ELAPSED" -ge "$KADEMLIA_MIN_WAIT" ] && [ "$GR" -ge 3 ] && [ "$LR" -ge 40 ]; then break; fi
+    if [ "$ELAPSED" -ge "$KADEMLIA_MIN_WAIT" ] && [ "$GR" -ge "$REQUIRED_CLIENT_REGS" ] && [ "$SELF" -ge 1 ] && [ "$LR" -ge 40 ]; then break; fi
     [ "$ELAPSED" -ge "$KADEMLIA_HARD_CAP" ] && break
     sleep 1
 done
-log "  Kademlia ready after $((SECONDS - KADEMLIA_T0))s ($GR gifter regs, $LR LEZ root events, kad mix peers: $MIX_PEERS_PER_NODE)"
+log "  Kademlia ready after $((SECONDS - KADEMLIA_T0))s ($GR/$REQUIRED_CLIENT_REGS client regs, self=$SELF, $LR LEZ root events, kad mix peers: $MIX_PEERS_PER_NODE)"
 
 RECEIVER_LOG="$STATE_DIR/chat_receiver.log"
 SENDER_LOG="$STATE_DIR/chat_sender.log"

vendor/nwaku

@@ -1 +1 @@
-Subproject commit 81c700ad80197069b4fdb9d43fb8886c1fca54a6
+Subproject commit 33d9d89e00be774d33ceafd3d59755d5a1089bb4