Wire up ePBS SSE events and fix envelope availability (#9199)

Co-Authored-By: Jimmy Chen <jchen.tc@gmail.com>

beacon_node/beacon_chain/src/payload_envelope_verification/mod.rs

@@ -60,6 +60,22 @@ pub struct AvailableEnvelope<E: EthSpec> {
 }
 
 impl<E: EthSpec> AvailableEnvelope<E> {
+    pub fn new(
+        execution_block_hash: ExecutionBlockHash,
+        envelope: Arc<SignedExecutionPayloadEnvelope<E>>,
+        columns: DataColumnSidecarList<E>,
+        columns_available_timestamp: Option<std::time::Duration>,
+        spec: Arc<ChainSpec>,
+    ) -> Self {
+        Self {
+            execution_block_hash,
+            envelope,
+            columns,
+            columns_available_timestamp,
+            spec,
+        }
+    }
+
     pub fn message(&self) -> &ExecutionPayloadEnvelope<E> {
         &self.envelope.message
     }
@@ -104,9 +120,10 @@ pub struct EnvelopeProcessingSnapshot<E: EthSpec> {
 ///    fully available.
 /// 2. `AvailabilityPending`: This envelope hasn't received all required blobs to consider it
 ///    fully available.
+#[allow(dead_code)]
 pub enum ExecutedEnvelope<E: EthSpec> {
     Available(AvailableExecutedEnvelope<E>),
-    // TODO(gloas) implement availability pending
+    // TODO(gloas): check data column availability via DA checker
     AvailabilityPending(),
 }
 
@@ -115,6 +132,7 @@ impl<E: EthSpec> ExecutedEnvelope<E> {
         envelope: MaybeAvailableEnvelope<E>,
         import_data: EnvelopeImportData<E>,
         payload_verification_outcome: PayloadVerificationOutcome,
+        spec: Arc<ChainSpec>,
     ) -> Self {
         match envelope {
             MaybeAvailableEnvelope::Available(available_envelope) => {
@@ -124,11 +142,15 @@ impl<E: EthSpec> ExecutedEnvelope<E> {
                     payload_verification_outcome,
                 ))
             }
-            // TODO(gloas) implement availability pending
+            // TODO(gloas): check data column availability via DA checker
             MaybeAvailableEnvelope::AvailabilityPending {
-                block_hash: _,
-                envelope: _,
-            } => Self::AvailabilityPending(),
+                block_hash,
+                envelope,
+            } => Self::Available(AvailableExecutedEnvelope::new(
+                AvailableEnvelope::new(block_hash, envelope, vec![], None, spec),
+                import_data,
+                payload_verification_outcome,
+            )),
         }
     }
 }