Ecotone: Extend P2P Request/Response format (#8927)

* Add specification for p2p req/resp Ecotone blocks

* Fix: Remove the res=1

specs/rollup-node-p2p.md

@@ -385,7 +385,7 @@ Response format: `<response> = <res><version><payload>`
   - `2` if invalid request
   - `3+` if other error
   - The `>= 128` range is reserved for future use.
-- `<version>` is a little-endian `uint32`, identifying the type of `ExecutionPayload` (fork-specific)
+- `<version>` is a little-endian `uint32`, identifying the response type (fork-specific)
 - `<payload>` is an encoded block, read till stream EOF.
 
 The input of `<response>` should be limited, as well as any generated decompressed output,
@@ -396,8 +396,9 @@ Implementations may opt for a different limit, since this sync method is optiona
 `<version>` list:
 
 - `0`: SSZ-encoded `ExecutionPayload`, with Snappy framing compression,
-  matching the `ExecutionPayload` SSZ definition of the L1 Merge, L2 Bedrock and L2 Regolith versions.
-- Other versions may be listed here with future network upgrades, such as the L1 Shanghai upgrade.
+  matching the `ExecutionPayload` SSZ definition of the L1 Merge, L2 Bedrock and L2 Regolith, L2 Canyon versions.
+- `1`: SSZ-encoded `ExecutionPayloadEnvelope` with Snappy framing compression,
+  matching the `ExecutionPayloadEnvelope` SSZ definition of the L2 Ecotone version.
 
 The request is by block-number, enabling parallel fetching of a chain across many peers.