Add macOS support for zstd installation

docs/demo.md

@@ -9,7 +9,7 @@
     ```bash
     cargo install tmkms --features=softsign --version=0.14.0
     ```
-- Install `zstd` using `sudo apt install zstd`
+- Install `zstd` using `sudo apt install zstd` (Linux) or `brew install zstd` (macOS)
 - testnet-state.zst ([exported testnet state](./run-first-validator.md#export-testnet-state))
 - LPS distribution Google spreadsheet URL or CSV file path
 

docs/export-testnet.md

@@ -4,7 +4,7 @@
 
 - Machine where the SAPO testnet validator node is already running
 
-  - Install `zstd` using `sudo apt install zstd`
+  - Install `zstd` using `sudo apt install zstd` (Linux) or `brew install zstd` (macOS)
 
   - [laconic-so](https://github.com/cerc-io/stack-orchestrator/?tab=readme-ov-file#install)
 

docs/run-first-validator.md

@@ -10,7 +10,7 @@
 
 - Machine 3: Where the genesis file is to be generated
 
-  - Install `zstd` using `sudo apt install zstd`
+  - Install `zstd` using `sudo apt install zstd` (Linux) or `brew install zstd` (macOS)
 
   - [LSP distribution JSON](./export-testnet.md#prepare-lps-distribution-json)
 

docs/run-validator.md

@@ -18,7 +18,7 @@
 
   - [ansible](playbooks/README.md#ansible-installation)
 
-  - Install `zstd` using `sudo apt install zstd`
+  - Install `zstd` using `sudo apt install zstd` (Linux) or `brew install zstd` (macOS)
 
 - Machine 3: Where the create-validator transaction is to be signed