docs(rooch-da): add instructions for tx list execution

Added detailed instructions and example command for executing a transaction list in Rooch DA, including expected output log for successful execution. This enhances clarity for users handling transaction execution.

crates/rooch/src/commands/da/README.md

@@ -78,4 +78,16 @@ rooch genesis init -d {data_dir} -n {network}
 ```
 
 we assume it's builtin genesis, because the target we want to verify is Rooch Network Mainnet/Testnet, all the two
-Network are using builtin genesis.
+Network are using builtin genesis.
+
+#### Execute tx list
+
+```shell
+rooch da exec --segment-dir {segment-dir} --order-state-path {order-state-path} -d {data-dir} -n {network} --btc-rpc-url {btc-rpc-url} --btc-rpc-user-name {btc-rpc-user-name} --btc-rpc-password {btc-rpc-password}
+```
+
+If everything is ok, you will see this log in the end:
+
+```shell
+2024-12-16T05:48:26.924094Z  INFO rooch::commands::da::commands::exec: All transactions execution state root are strictly equal to RoochNetwork: [0, {end_order}]
+```