docs: add readme for super root checker to link in governance post (#16065)

* docs: add readme for super root check to link in governance post

* docs: more correct wording

Co-authored-by: Adrian Sutton <[email protected]>

* docs: make trust assumptions more clear for the endpoint usage

---------

Co-authored-by: Adrian Sutton <[email protected]>

Author: stevennevins

op-chain-ops/cmd/check-super-root/README.md

@@ -0,0 +1,48 @@
+# Overview
+
+Generating the first SuperRoot used for an Interop migration
+
+## Prerequisites:
+
+1. git clone or pull the latest develop branch of the optimism repo
+2. Go Installed
+    - You can follow the instructions in the [CONTRIBUTING.md](http://CONTRIBUTING.md) to install all software dependencies of the repo
+3. RPC URLs for the **L2** chains you want to generate a super root for.
+   - **Important**: These RPC endpoints must be trusted endpoints as they provide the chain state used to compute the SuperRoot.
+
+## Generation:
+
+A SuperRoot with this script can be generated at a provided timestamp or if none is provided then the SuperRoot nearest to the current finalized timestamp will be found.
+
+```bash
+go run op-chain-ops/cmd/check-super-root/main.go --rpc-endpoints $RPC_URL_1,$RPC_URL_2
+```
+
+Output:
+
+```bash
+INFO [05-19|16:24:50.736] Super root calculated successfully superRoot=**0xa47cfdd734e7db568eea0531c5fa6117398a5218d76371a17656e13836a8a44f** timestamp=1,747,682,546 chains=2
+```
+
+Record the bytes32 hash of the super root and the timestamp the SuperRoot is valid for
+
+## Environment Variables
+
+Alternatively, you can use environment variables to configure the script:
+
+- `CHECK_SUPER_ROOT_RPC_ENDPOINTS`: Comma-separated list of L2 execution client RPC endpoints.
+- `CHECK_SUPER_ROOT_TIMESTAMP`: Target timestamp for super root calculation.
+
+# Validation Checks
+
+A SuperRoot can be validated with the script and providing the timestamp the SuperRoot was created for:
+
+```bash
+go run op-chain-ops/cmd/check-super-root/main.go --rpc-endpoints $RPC_URL_1,$RPC_URL_2 --timestamp $SUPER_ROOT_TIMESTAMP
+```
+
+The output should match the above
+
+```bash
+INFO [05-19|16:24:50.736] Super root calculated successfully superRoot=**0xa47cfdd734e7db568eea0531c5fa6117398a5218d76371a17656e13836a8a44f** timestamp=1,747,682,546 chains=2
+```