XChain Platform 0.9.0

XChain Platform 0.9.0

First release of the XChain Platform release train. Every train component now
shares one platform version, so XChain 0.9.0 names an exact, reproducible set
of software rather than a rough era.

Resolved component set

Component	Version	Changed this train
xchain-vm	0.9.0	yes
xchain-decoder	0.9.0	yes
xchain-indexer	0.9.0	yes
xchain-hub	0.9.0	yes
xchain-sync	0.9.0	yes
xchain-node	0.9.0	yes
xchain-encoder	0.9.0	yes
xchain-utxo-tracker	0.9.0	yes
xchain-explorer	0.9.0	yes

All nine changed, because this is the adoption jump onto the shared stream.

The version numbers go DOWN, deliberately

The platform stream starts at 0.9.0 for the testnet series; 1.0.0 is reserved
for mainnet. Most components carried a higher number in their own stream
(xchain-indexer was 2.7.17). A higher legacy number is an OLDER release.
Each changelog marks the boundary in place.

Install

xchain-node install v0.9.0     # this exact pinned set
xchain-node install            # resolves the latest release, same thing today

Both install every service and every bundled library at the commit
release-manifest.json pins, and verify each checkout against it.

Verify this release

git tag -v v0.9.0
gpg --verify SHA256SUMS.asc SHA256SUMS
sha256sum -c SHA256SUMS

Signed with the XChain Platform release key,
1DA7 C489 6F56 EA22 CF49 1EDF 4361 611A 82F9 0B70. See
Release Signing.

Known issues

Three suites are red for reasons that predate this release and are unchanged
by it: xchain-hub regression, xchain-sync e2e, and xchain-explorer
perf/integration/conformance. They were surfaced when CI began running again and
are tracked for follow-up. The hub failures include a slashing-counter reset
defect, so operators running validators should follow that work.