Notify reprocessing queue after RPC custody column imports

[0u-Y]

Issue Addressed

An RPC-fetched payload envelope can complete execution verification while remaining pending on custody columns. When RPC custody columns subsequently complete the import, process_rpc_custody_columns recomputes the head but does not notify the reprocessing queue.

As a result, attestations waiting for the payload envelope are not released by this import event and can remain queued until the existing fallback runs.

The same RPC completion branch also handles pre-Gloas block imports.

Proposed Changes

Call the existing notify_import_after_column helper after successful import and head recomputation, using the slot and root returned by AvailabilityProcessingStatus::Imported.

This matches the existing gossip column completion paths and emits the appropriate event:

• PayloadEnvelopeImported for Gloas.
• BlockImported for pre-Gloas.

Add regression tests covering deferred envelope import under Gloas and deferred block import under Fulu. The tests check the event type and root, with no additional event in each tested sequence. The Gloas test also checks that no completion event is emitted while the envelope is still awaiting columns.

Additional Info

Both new regression tests failed before the production change and passed afterward:

FORK_NAME=gloas cargo test --release -p network \
  --features fork_from_env \
  rpc_columns_notify_after_deferred_envelope_import

FORK_NAME=fulu cargo test --release -p network \
  --features fork_from_env \
  rpc_columns_notify_after_deferred_block_import

The existing release_awaiting_attestations_on_payload_envelope_imported consumer test also passed. These tests cover the network processor notification and queue consumer separately; they are not a full network E2E test.

AI assistance was used for the regression tests, and this PR description.

[pawanjay176]

LGTM, thanks!

[mergify]

Queued — the merge queue status continues in this comment ↓.

[mergify]

Merge Queue Status

• ✅ Entered queue — 2026-09-28 19:10 UTC · Rule: default · triggered by @pawanjay176 with the merge queue checkbox
• ✅ Checks passed · on draft merge queue: checking #10128 + #10137 together on unstable (1914c4d) #10144
• ✅ Merged — 2026-09-28 19:42 UTC · at b8c15970a5aced6d31be2d605185479a761819ee · squash

This pull request spent 32 minutes 23 seconds in the queue, including 29 minutes 57 seconds running CI.

Required conditions to merge

• check-success=local-testnet-success
• check-success=test-suite-success
• github-review-approved [🛡 GitHub branch protection]
  • Notify reprocessing queue after RPC custody column imports #10128
  • Use block hash in payload invalidation tests #10137