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>

reference-rpc-endpoint.sh

@@ -13,6 +13,37 @@ if [ ! -f "$json_file" ]; then
     exit 1
 fi
 
+# Look up urls by registry key (drpc slug from the compose x-upstreams chain label).
+# Works for non-EVM chains that have no chainid in the registry.
+if [ "$1" = "--chain" ]; then
+    if [ $# -lt 2 ]; then
+        echo "Usage: $0 --chain <slug>"
+        exit 1
+    fi
+    urls=$(jq -r --arg k "$2" '.[$k].urls // [] | .[]' "$json_file" 2>/dev/null | tr '\n' ' ')
+    if [ -z "${urls// /}" ]; then
+        echo "Chain not found: $2"
+        exit 1
+    fi
+    echo "$urls"
+    exit 0
+fi
+
+# Look up the protocol family for a registry key (eth, starknet, aztec, bitcoin, solana, ...)
+if [ "$1" = "--protocol" ]; then
+    if [ $# -lt 2 ]; then
+        echo "Usage: $0 --protocol <slug>"
+        exit 1
+    fi
+    protocol=$(jq -r --arg k "$2" 'if has($k) then (.[$k].protocol // "eth") else empty end' "$json_file" 2>/dev/null)
+    if [ -z "$protocol" ]; then
+        echo "Chain not found: $2"
+        exit 1
+    fi
+    echo "$protocol"
+    exit 0
+fi
+
 # Look up by rollup_version (for Aztec: version from result.header.globalVariables.version)
 if [ "$1" = "--rollup-version" ]; then
     if [ $# -lt 2 ]; then