superseed-sepolia: consensus-layer sync + debug_geth L1 + drop genesis blob fields

op-reth/op-geth sepolia now run op-node consensus-layer sync (empty DB is never
P2P-backfilled) with --disable-discovery, derive L1 via debug_geth against an
operator-set full-history Sepolia RPC (SUPERSEED_SEPOLIA_L1_EXECUTION_RPC, falling
back to ETHEREUM_SEPOLIA_EXECUTION_RPC), and serve a genesis.json with the invalid
top-level excessBlobGas/blobGasUsed nulls removed (eip1559DenominatorCanyon=250
retained). Regenerated from the vibe-node generator.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

op/superseed/sepolia/genesis.json

@@ -14481,7 +14481,5 @@
     "number": "0x0",
     "gasUsed": "0x0",
     "parentHash": "0x0000000000000000000000000000000000000000000000000000000000000000",
-    "baseFeePerGas": "0x3b9aca00",
-    "excessBlobGas": null,
-    "blobGasUsed": null
+    "baseFeePerGas": "0x3b9aca00"
   }