feat(docs): Add aztec-wallet proving

docs/docs/guides/developer_guides/local_env/sandbox_proving.md

@@ -20,7 +20,7 @@ To enable client-side proving, update the docker compose file found at `~/.aztec
 ```yml
 BB_BINARY_PATH: /usr/src/barretenberg/cpp/build/bin/bb
 PXE_PROVER_ENABLED: 1
-BB_WORKING_DIRECTORY: ~/bb-temp    #any temp directory for writing circuit artifacts
+BB_WORKING_DIRECTORY: ~/bb-temp #any temp directory for writing circuit artifacts
 ```
 
 ## Usage
@@ -36,3 +36,28 @@ The sandbox will take much longer to start. The first time it starts, it will ne
 The sandbox will also deploy 3 Schnorr account contracts on startup. The sandbox will need to generate transaction proofs for deployment, which will take additional time.
 
 Once everything has been set up, you will see that the PXE is listening on `localhost:8080` as you would see with the sandbox running in the default mode. At this point you can use the sandbox as you would without client-side proving enabled.
+
+## Proving with `aztec-wallet`
+
+Alternatively, you can enable proving for transactions using `aztec-wallet` and not all transactions going to the sandbox.
+
+Open `~/.aztec/bin/aztec-wallet` and update the `ENV_VARS_TO_INJECT` variable to:
+
+```bash
+# ~/.aztec/bin/aztec-wallet
+export ENV_VARS_TO_INJECT="WALLET_DATA_DIRECTORY SSH_AUTH_SOCK BB_BINARY_PATH PXE_PROVER_ENABLED BB_WORKING_DIRECTORY"
+```
+
+Export the following envnironment variables in the terminal where you will run `aztec-wallet` commands:
+
+```bash
+export BB_BINARY_PATH=/usr/src/barretenberg/cpp/build/bin/bb
+export PXE_PROVER_ENABLED=1
+export BB_WORKING_DIRECTORY=~/bb-temp
+```
+
+Now send transactions from `aztec-wallet`, and proving will be enabled.
+
+Note that you do not need to restart the sandbox in order to start sending proven transactions. You can optionally set this for 1 off transactions.
+
+If this is the first time you are sending transactions with proving enabled, you will have to download the CRS (which is several GBs).