#7603
#### Custody backfill sync service
Similar in many ways to the current backfill service. There may be ways to unify the two services. The difficulty there is that the current backfill service tightly couples blocks and their associated blobs/data columns. Any attempts to unify the two services should be left to a separate PR in my opinion.
#### `SyncNeworkContext`
`SyncNetworkContext` manages custody sync data columns by range requests separetly from other sync RPC requests. I think this is a nice separation considering that custody backfill is its own service.
#### Data column import logic
The import logic verifies KZG committments and that the data columns block root matches the block root in the nodes store before importing columns
#### New channel to send messages to `SyncManager`
Now external services can communicate with the `SyncManager`. In this PR this channel is used to trigger a custody sync. Alternatively we may be able to use the existing `mpsc` channel that the `SyncNetworkContext` uses to communicate with the `SyncManager`. I will spend some time reviewing this.
Co-Authored-By: Eitan Seri-Levi <eserilev@ucsc.edu>
Co-Authored-By: Eitan Seri- Levi <eserilev@gmail.com>
Co-Authored-By: dapplion <35266934+dapplion@users.noreply.github.com>
This PR adds the following sync tests to CI workflow - triggered when a PR is labeled `syncing` - to ensure we have some e2e coverage on basic sync scenarios:
- [x] checkpoint sync to a live network (covers range and backfill sync for _current_ fork)
- [x] checkpoint sync to a running devnet (covers range and backfill sync for _next_ fork)
It seems to work fine running on github hosted runners - but if performance become an issue we could switch to using self hosted runners for sepolia sync test. (standard CPU runners have 4 CPU, 16 GB ram - i think it _should_ be enough on sepolia / devnet networks)
The following tests have been **removed** from this PR and moved to a separate issue *(#7550)
- [x] genesis sync on a local devnet (covers current and next fork)
- [x] brief shutdown and restart (covers lookup sync)
- [x] longer shutdown and restart (covers range sync)
I'm hoping to keep these e2e test maintenance effort to a minimum - hopefully longer term we could have some generic e2e tests that works for all clients and the maintenance effort can be spread across teams.
### Latest test run:
https://github.com/sigp/lighthouse/actions/runs/15411744248
### Results:
<img width="687" alt="image" src="https://github.com/user-attachments/assets/c7178291-7b39-4f3b-a339-d3715eb16081" />
<img width="693" alt="image" src="https://github.com/user-attachments/assets/a8fc3520-296c-4baf-ae1e-1e887e660a3c" />
#### logs are available as artifacts:
<img width="629" alt="image" src="https://github.com/user-attachments/assets/3c0e1cd7-9c94-4d0c-be62-5e45179ab8f3" />
