Gloas payload cache (#9209)

In Gloas, beacon blocks are imported into fork choice immediately - the payload envelope and data columns arrive
separately. KZG commitments moved from the column sidecar into the execution payload bid, so the existing
`DataAvailabilityChecker` (which assumes block and data are coupled) can't be used for Gloas.


  * Introduced `PendingPayloadCache` to keep track of payload and data columns per block root.
* Added gossip column verification
* Added support for Gloas data column reconstruction
* Payload envelope verification simplified: removed `MaybeAvailableEnvelope`, `ExecutedEnvelope`, `EnvelopeImportData`

Not yet implemented (tracked with TODOs):
- Proper lookup sync for Gloas columns arriving before blocks
- Partial column merging for Gloas
- Moving `load_gloas_payload_bid` disk reads off the async runtime
- Backfill/range sync for Gloas

Based on @eserilev's PR and work in progress. See also #9202 for verification.


Co-Authored-By: Eitan Seri-Levi <eserilev@ucsc.edu>

Co-Authored-By: Eitan Seri- Levi <eserilev@gmail.com>

Co-Authored-By: Daniel Knopik <daniel@dknopik.de>

Co-Authored-By: Daniel Knopik <107140945+dknopik@users.noreply.github.com>

Co-Authored-By: dapplion <35266934+dapplion@users.noreply.github.com>

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

beacon_node/beacon_chain/src/metrics.rs

@@ -2043,6 +2043,12 @@ pub static DATA_AVAILABILITY_OVERFLOW_MEMORY_BLOCK_CACHE_SIZE: LazyLock<Result<I
             "Number of entries in the data availability overflow block memory cache.",
         )
     });
+pub static PENDING_PAYLOAD_CACHE_SIZE: LazyLock<Result<IntGauge>> = LazyLock::new(|| {
+    try_create_int_gauge(
+        "pending_payload_cache_size",
+        "Number of entries in the pending payload availability cache.",
+    )
+});
 pub static DATA_AVAILABILITY_RECONSTRUCTION_TIME: LazyLock<Result<Histogram>> =
     LazyLock::new(|| {
         try_create_histogram(
@@ -2150,6 +2156,10 @@ pub fn scrape_for_metrics<T: BeaconChainTypes>(beacon_chain: &BeaconChain<T>) {
         &DATA_AVAILABILITY_OVERFLOW_MEMORY_BLOCK_CACHE_SIZE,
         da_checker_metrics.block_cache_size,
     );
+    set_gauge_by_usize(
+        &PENDING_PAYLOAD_CACHE_SIZE,
+        beacon_chain.pending_payload_cache.cache_size(),
+    );
 
     if let Some((size, num_lookups)) = beacon_chain.pre_finalization_block_cache.metrics() {
         set_gauge_by_usize(&PRE_FINALIZATION_BLOCK_CACHE_SIZE, size);