superseed-sepolia: add pectra_blob_schedule_time + fix eip1559DenominatorCanyon

op-node was crashing post-Jovian and the rollup/genesis configs were missing
two fields present in the live sequencer (sepolia.superseed.xyz
optimism_rollupConfig):
- rollup.json: add pectra_blob_schedule_time=1742486400 (L1 Sepolia Pectra)
- genesis.json: eip1559DenominatorCanyon 0 -> 250 (match chain_op_config)

Verified against the live sequencer. Fixes op-node 'unexpected length: 178'
L1-info parse error. karst_time not yet published by the sequencer (Karst
Sepolia ~2026-06-17 16:00 UTC) - to be added once available.

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

op/superseed/sepolia/genesis.json

@@ -30,7 +30,7 @@
       "optimism": {
         "eip1559Elasticity": 6,
         "eip1559Denominator": 50,
-        "eip1559DenominatorCanyon": 0
+        "eip1559DenominatorCanyon": 250
       }
     },
     "nonce": "0x0",

op/superseed/sepolia/rollup.json

@@ -36,6 +36,7 @@
   "holocene_time": 1732633200,
   "isthmus_time": 1744905600,
   "jovian_time": 1768978801,
+  "pectra_blob_schedule_time": 1742486400,
   "batch_inbox_address": "0x3a81f59e6bf4238d1ed202f3b06389454de3f204",
   "deposit_contract_address": "0x7a0db8c51432d2c3eb4e8f360a2eeb26ff2809fb",
   "l1_system_config_address": "0x4df2f170214198df84716b89c84b0c177c39f6c9"