Add changelog and some documentation

Signed-off-by: Sasha Bogicevic <[email protected]>

Author: v0d1ch

CHANGELOG.md

@@ -48,6 +48,8 @@ changes.
 
 - Add API query (GET /head) to fetch the latest head state by a node and help introspecting the whole internal state.
 
+- Provide `--network` option to hydra-node in order to use pre-published hydra scripts.
+
 ## [0.21.0] - 2025-04-28
 
 - New metric for counting the number of active peers: `hydra_head_peers_connected`

docs/docs/configuration.md

@@ -52,7 +52,7 @@ Being a protocol parameter, all participants in a head must configure the same `
 
 :::
 
-The default contestation period is _600 seconds_, but it should be tailored to the network conditions, as different networks have varying block production rates. A good rule of thumb is the maximum time you would expect an attacker to launch a withholding attack onto the cardano network you are on. Also, consider the time it takes to propagate a transaction to the network and the time it takes for a block to be produced, and the contestation period should be long enough to accommodate any downtime of the `hydra-node`. 
+The default contestation period is _600 seconds_, but it should be tailored to the network conditions, as different networks have varying block production rates. A good rule of thumb is the maximum time you would expect an attacker to launch a withholding attack onto the cardano network you are on. Also, consider the time it takes to propagate a transaction to the network and the time it takes for a block to be produced, and the contestation period should be long enough to accomodate any downtime of the `hydra-node`.
 
 The contestation deadline decides when a closed head can be fanned out. At worst, this is `(1 + n) * CP` after submitting a `Close` transaction, where `n` is the number of participants in the head. This is because the deadline is pushed forward on each `Contest`. With no contestations which may still be `2 * CP` after `Close` depending on the upper validity set on che close transaction. The `hydra-node` currently picks a blanket 200 seconds as [max grace time](https://hydra.family/head-protocol/haddock/hydra-node/Hydra-Chain-Direct-Handlers.html#v:maxGraceTime).
 
@@ -83,6 +83,8 @@ See the [how-to](./how-to/incremental-commit) and [protocol documentation](./dev
 
 The `hydra-node` uses reference scripts to reduce transaction sizes driving the head's lifecycle. Specify the `--hydra-scripts-tx-id` to reference the correct scripts. The `hydra-node` will verify the availability of these scripts on-chain.
 
+Since we pre-publish hydra scrips before each release, in case you want to run the official released version instead of specifying hydra-scripts using `--hydra-scripts-tx-id`, you can use `--network` together with the network name you would like to run your hydra-node on (e.g. `--network preview`).
+
 Check the scripts against which a hydra-node was compiled using:
 
 ```shell