Upgrade nodes in CI tests

[meddle0x53]

Motivation

To test upgrading snarkos versions in a network we run a special denvet test as described in #4026

Test Plan

Run the CI and the new test passes.

Documentation

The test works following the steps:

1. Download latest snarkOS release source from GitHub.
2. Build it via cargo install --locked --path . --features test_network into a separate prefix (SNARKOS_RELEASE_DIR).
3. Probe latest_consensus_version for release and PR binaries.
4. Compute CONSENSUS_VERSION_HEIGHTS for release and PR.
5. Rebuild release snarkOS with its heights.
6. Rebuild PR snarkOS with its heights.
7. Start a devnet with the release binary.
8. Restart nodes one-by-one to the PR binary.

Added a new workflow for the new test, extracting it from the devnet tests, as it is time-taking with all the compilations and waiting on the consensus version.

[vicsn]

LGTM, let's await Kai's review

[kaimast]

Looks good to me! I pushed one more commit with some minor cleanups (83355c6).

I also rebased #3902 on it. That PR has some networking changes and the tests succeed. We might still want to test it with a branch that has breaking changes to see that those are caught, or did you do that already?

Also, a side note, it would be great if we could keep the number of commits in PRs to a manageable amount. This one has 14 commits, for ~700 LOC. It's not a huge deal, but it can be a pain when reading the commit logs and or when using git bisect.

[meddle0x53]

@kaimast @vicsn Squashed all into one commit now.

[vicsn]

@kaimast good idea. You want to give it another go with a toy PR which changes the gateway handshake in a breaking way?

[vicsn]

We might still want to test it with a branch that has breaking changes to see that those are caught, or did you do that already?

@meddle0x53 can you try on a toy commit which makes a breaking change to both struct ChallengeRequest objects?

[meddle0x53]

Yeah if I update ChallengeRequest the test fails and I get:

2026-01-07T13:03:59.066676Z DEBUG [MemoryPool] Shaking hands with 127.0.0.1:5003...
2026-01-07T13:03:59.066786Z DEBUG [MemoryPool] Shaking hands with 127.0.0.1:5002...
2026-01-07T13:03:59.066822Z DEBUG [MemoryPool] Shaking hands with 127.0.0.1:5001...
2026-01-07T13:03:59.068359Z  WARN [MemoryPool] Unable to connect to '127.0.0.1:5002' - I/O error: [MemoryPool] the peer disconnected before sending "Event::ChallengeResponse", likely due to peer saturation or shutdown
2026-01-07T13:03:59.068460Z  WARN [MemoryPool] Unable to connect to '127.0.0.1:5003' - I/O error: [MemoryPool] the peer disconnected before sending "Event::ChallengeResponse", likely due to peer saturation or shutdown
2026-01-07T13:03:59.068884Z  WARN [MemoryPool] Unable to connect to '127.0.0.1:5001' - I/O error: [MemoryPool] the peer disconnected before sending "Event::ChallengeResponse", likely due to peer saturation or shutdown
2026-01-07T13:04:00.579279Z DEBUG Skipping batch proposal for round 112 (node is syncing)
2026-01-07T13:04:01.410926Z  INFO Received 'GET /block/height/latest' from '127.0.0.1:54017'
2026-01-07T13:04:03.081466Z DEBUG Skipping batch proposal for round 112 (node is syncing)
2026-01-07T13:04:05.583033Z DEBUG Skipping batch proposal for round 112 (node is syncing)
2026-01-07T13:04:06.454622Z  INFO Received 'GET /block/height/latest' from '127.0.0.1:54020'
2026-01-07T13:04:08.085138Z DEBUG Skipping batch proposal for round 112 (node is syncing)
2026-01-07T13:04:10.587016Z DEBUG Skipping batch proposal for round 112 (node is syncing)
2026-01-07T13:04:11.504465Z  INFO Received 'GET /block/height/latest' from '127.0.0.1:54026'
2026-01-07T13:04:13.089705Z DEBUG Skipping batch proposal for round 112 (node is syncing)
2026-01-07T13:04:14.067889Z  INFO No connected validators
2026-01-07T13:04:14.068108Z DEBUG   Not connected to aleo1ashyu96tjwe63u0gtnnv8z5lhapdu4l5pjsl2kha7fv7hvz2eqxs5dz0rg (25.00% of total stake)
2026-01-07T13:04:14.068159Z DEBUG   Not connected to aleo12ux3gdauck0v60westgcpqj7v8rrcr3v346e4jtq04q7kkt22czsh808v2 (25.00% of total stake)
2026-01-07T13:04:14.068205Z DEBUG   Not connected to aleo1s3ws5tra87fjycnjrwsjcrnw2qxr8jfqqdugnf0xzqqw29q9m5pqem2u4t (25.00% of total stake)
2026-01-07T13:04:14.068246Z  WARN Not connected to 3 validators (of 3 bonded validators) (75.00% of total stake not connected)

Logs like this, @vicsn