Group branches.yaml by EL/CL/MEV/ZK/Tooling/Other/Lean (#386)

## Summary
- Restructures `branches.yaml` so each top-level key is a group (`el`,
`cl`, `mev`, `zk`, `tooling`, `other`, `lean`) instead of a flat client
dict
- Each group can declare `common_branches:` that get merged into every
client in the group, with `skip_common: true` as a per-client opt-out —
devnet branches (`bal-devnet-3`/`bal-devnet-7`/`glamsterdam-devnet-4`
for EL, `glamsterdam-devnet-4` for CL) are now written once per group
rather than repeated under every client
- `generate_config.py` gains a small `flatten_groups()` step that runs
before the existing expansion logic, so the rest of the script is
untouched and the generated `config.yaml` is byte-identical to before

### Common-branch opt-outs
- `el.common_branches`: opted out by `ethereumjs`
- `cl.common_branches`: opted out by `caplin`, `consensoor`

## Test plan
- [x] `python3 generate_config.py` runs cleanly and reports 148
configurations (same as before)
- [x] Per-client branch lists verified identical pre/post for every EL
and CL client (besu, erigon, ethereumjs, ethrex, geth, nethermind,
nimbus-eth1, reth, caplin, consensoor, grandine, lighthouse, lodestar,
nimbus-eth2, prysm-beacon-chain, teku)
- [x] 39 distinct client repositories in the generated `config.yaml` (37
base + prysm/nimbus splits) — none lost
- [ ] Sanity-check a scheduled build run against this branch before
merging

Author: barnabasbusa

.github/actions/install-deps/action.yml

@@ -23,9 +23,9 @@ runs:
       distribution: 'temurin'
       java-version: '25'
   - uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
-    if: contains(inputs.repository, 'lodestar') || contains(inputs.repository, 'ethereumjs')
+    if: contains(inputs.repository, 'lodestar')
     with:
-      node-version: 20
+      node-version: 24
       check-latest: true
   - uses: actions/setup-go@4b73464bb391d4059bd26b0524d20df3927bd417 # v6.3.0
     if: contains(inputs.repository, 'prysm')

.github/workflows/build-push-ethereumjs.yml

@@ -9,7 +9,6 @@ Run the *Build **client*** workflow;
 - [Build Dummy-EL](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-dummy-el.yml) [[source](https://github.com/ethpandaops/dummy-el)]
 - [Build Eleel](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-eleel.yml) [[source](https://github.com/sigp/eleel)]
 - [Build Erigon](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-erigon.yml) [[source](https://github.com/ledgerwatch/erigon)]
-- [Build EthereumJS](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-ethereumjs.yml) [[source](https://github.com/ethereumjs/ethereumjs-monorepo)]
 - [Build Ethrex](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-ethrex.yml) [[source](https://github.com/lambdaclass/ethrex)]
 - [Build Geth](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-geth.yml) [[source](https://github.com/ethereum/go-ethereum)]
 - [Build Lighthouse](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-lighthouse.yml) [[source](https://github.com/sigp/lighthouse)]
@@ -32,7 +31,6 @@ Run the *Build **tooling*** workflow;
 - [Build consesnus-monitor](https://github.com/ethpandaops/eth-client-docker-image-builder/blob/master/.github/workflows/build-push-consensus-monitor.yml) [[source](https://github.com/ralexstokes/ethereum_consensus_monitor)]
 - [Build execution-monitor](https://github.com/ethpandaops/eth-client-docker-image-builder/blob/master/.github/workflows/build-push-execution-monitor.yml) [[source](https://github.com/ethereum/nodemonitor)]
 - [Build beacon-metrics-gazer](https://github.com/ethpandaops/eth-client-docker-image-builder/blob/master/.github/workflows/build-push-beacon-metrics-gazer.yml) [[source](https://github.com/dapplion/beacon-metrics-gazer)]
-- [Build goomy-blob](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-goomy-blob.yaml) [[source](https://github.com/ethpandaops/goomy-blob)]
 - [Build ethereum-genesis-generator](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-genesis-generator.yml) [[source](https://github.com/ethpandaops/ethereum-genesis-generator)]
 - [Build mev-rs](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-mev-rs.yml) [[source](https://github.com/ralexstokes/mev-rs)]
 - [Build reth-rbuilder](https://github.com/ethpandaops/eth-client-docker-image-builder/actions/workflows/build-push-reth-rbuilder.yml) [[source](https://github.com/flashbots/rbuilder)]