docs: Add v0.28.0 migration guide (#2067)

* docs: Add v0.28.0 migration guide

* Set commit hash in version

migrate/v0_28/migrate.md

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+# Kava 18 Upgrade Instructions
+
+## Software Version and Key Dates
+
+- The version of `kava` for Kava 18 is `v0.28.0`
+- The Kava 18 chain will be shutdown with a `SoftwareUpgradeProposal` that
+  activates at height 14136737 at approximately 15:00 UTC on February 25, 2025.
+
+## Dependency Changes
+
+packet-forwarding-middleware is updated to resolve unreliability of USDT IBC
+transactions.
+
+### For validators using RocksDB
+
+> [!NOTE]
+> If you use goleveldb or other database backends, this is not required.
+
+There are no changes in rocksDB version requirements for this upgrade.
+
+Same as the previous version, the recommended RocksDB version is `v9.3.1`.
+
+Please reference the [RocksDB repository](https://github.com/facebook/rocksdb/tree/v9.3.1) to update your installation before building the RocksDB kava binary.
+
+Node operators using rocksdb are encouraged to [use `tcmalloc` as their memory allocator](https://github.com/Kava-Labs/kava/blob/v0.26.2-iavl-v1/migrate/v0_26/iavl-v1.md#default-memory-allocator).
+
+## On the day of the upgrade
+
+The kava chain is expected to halt at block height **14136737**.
+**Do not stop your node and begin the upgrade before the upgrade height**,
+or you may go offline and be unable to recover until after the upgrade!
+
+**Make sure the kava process is stopped before proceeding and that you have backed up your validator**.
+Failure to backup your validator could make it impossible to restart your node if the upgrade fails.
+
+**Ensure you are using golang 1.22.7+ and not a different version.** Golang 1.22.6 and below may cause app hash mismatches!
+
+To update to v0.28.0
+
+```sh
+# check go version - look for 1.22.7+!
+go version
+# go version go1.22.9 linux/amd64
+
+# in the `kava` folder
+git fetch
+git checkout v0.28.0
+
+# Note: Golang 1.22.7+ must be installed before this step
+make install
+
+# verify versions
+kava version --long
+# build_deps:
+#  ...
+# build_tags: netgo ledger,
+# commit: d9ce773f62418183beac2e9168c7cfafa30bc508
+# cosmos_sdk_version: v0.47.15
+# go: go version go1.22.9 linux/amd64
+# name: kava
+# server_name: kava
+# version: 0.28.0
+
+# Restart node -
+kava start
+```
+
+### Risks
+
+As a validator, performing the upgrade procedure on your consensus nodes carries
+a heightened risk of double-signing and being slashed. The most important piece
+of this procedure is verifying your software version and genesis file hash
+before starting your validator and signing.
+
+The riskiest thing a validator can do is discover that they made a mistake and
+repeat the upgrade procedure again during the network startup. If you discover a
+mistake in the process, the best thing to do is wait for the network to start
+before correcting it. If the network is halted and you have started with a
+different genesis file than the expected one, seek advice from a Kava developer
+before resetting your validator.
+
+### Recovery
+
+Prior to applying the Kava 18 upgrade, validators are encouraged to take a full
+data snapshot at the upgrade height before proceeding. Snap-shotting depends
+heavily on infrastructure, but generally this can be done by backing up the
+.kava directory.
+
+It is critically important to back-up the .kava/data/priv_validator_state.json
+file after stopping your kava process. This file is updated every block as your
+validator participates in consensus rounds. It is a critical file needed to
+prevent double-signing, in case the upgrade fails and the previous chain needs
+to be restarted.
+
+In the event that the upgrade does not succeed, validators and operators must
+downgrade back to v0.27.x of the Kava software and restore to their latest
+snapshot before restarting their nodes.
+
+### Coordination
+
+If the Kava 18 chain does not launch by February 26th at 00:00 UTC, the launch
+should be considered a failure. In the event of launch failure, coordination
+will occur in the [Kava discord](https://discord.com/invite/kQzh3Uv).