monitoring scripts: protocol dispatch via registry slug + mantle/metis chainid fixes

- sync-status.sh: resolve protocol family from the compose x-upstreams chain
  label via the registry (reference-rpc-endpoint.sh --protocol) instead of
  path-substring guessing; legacy path detection kept as fallback for
  composes without a resolved label. Unknown families report
  'unsupported protocol: X' honestly instead of a bogus eth_chainId error.
  Aztec reference lookup falls back to slug urls when rollup_version is
  not in the registry.
- reference-rpc-endpoint.sh: new --chain <slug> (urls by registry key,
  works for idless non-EVM entries) and --protocol <slug> modes; existing
  chainid and --rollup-version lookups unchanged.
- mantle-sepolia: chainid 5001 -> 5003 (verified live: 0x138b), label and
  --networkid now correct
- metis-sepolia: label resolves via registry override (drpc chains.yaml
  carries wrong id 59901; live chain is 59902, verified via official RPC)

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

sync-status.sh

@@ -34,17 +34,41 @@ for path in $pathlist; do
     if $include; then
         RPC_URL="$PROTO://$DOMAIN/$path"
 
-        # Detect Starknet vs Ethereum vs Aztec based on path
-        if echo "$path" | grep -qi "starknet"; then
-            is_starknet=true
-            is_aztec=false
-        elif echo "$path" | grep -qi "aztec"; then
-            is_starknet=false
-            is_aztec=true
-        else
-            is_starknet=false
-            is_aztec=false
+        # Resolve the protocol family from the compose x-upstreams chain label
+        # (drpc slug) via the registry. Falls back to legacy path-substring
+        # detection for composes without a resolved chain label.
+        chain_slug=$(grep -oP '^\s*chain:\s*\K\S+' "$BASEPATH/$1.yml" 2>/dev/null | head -1)
+        protocol=""
+        if [ -n "$chain_slug" ]; then
+            protocol=$($BASEPATH/reference-rpc-endpoint.sh --protocol "$chain_slug" 2>/dev/null) || protocol=""
         fi
+        if [ -z "$protocol" ]; then
+            # Legacy detection by path substring
+            if echo "$path" | grep -qi "starknet"; then
+                protocol="starknet"
+            elif echo "$path" | grep -qi "aztec"; then
+                protocol="aztec"
+            else
+                protocol="eth"
+            fi
+        fi
+
+        case "$protocol" in
+            eth|starknet|aztec)
+                ;;
+            *)
+                # Protocol family known from the registry but no probe support
+                # in check-health.sh yet - honest output instead of a bogus
+                # eth_chainId error. Add a handler when we deploy such a node.
+                echo "unsupported protocol: $protocol ($chain_slug)"
+                exit 1
+                ;;
+        esac
+
+        is_starknet=false
+        is_aztec=false
+        [ "$protocol" = "starknet" ] && is_starknet=true
+        [ "$protocol" = "aztec" ] && is_aztec=true
 
         ref=''
         if [ -n "$2" ]; then
@@ -67,8 +91,14 @@ for path in $pathlist; do
                 version_hex="${version_hex#0x}"
                 version_hex="${version_hex: -8}"
                 version_decimal=$((16#$version_hex))
-                ref=$($BASEPATH/reference-rpc-endpoint.sh --rollup-version "$version_decimal")
-                if [ $? -ne 0 ]; then
+                ref=$($BASEPATH/reference-rpc-endpoint.sh --rollup-version "$version_decimal" 2>/dev/null)
+                if [ $? -ne 0 ] || [ -z "$ref" ]; then
+                    # Fallback: reference urls by chain slug from the compose label
+                    if [ -n "$chain_slug" ]; then
+                        ref=$($BASEPATH/reference-rpc-endpoint.sh --chain "$chain_slug" 2>/dev/null) || ref=""
+                    fi
+                fi
+                if [ -z "$ref" ]; then
                     echo "error: no reference endpoint for Aztec rollup_version $version_decimal"
                     exit 1
                 fi