docs: foundry-evm-fuzz extensions

Author: grandizzy

crates/evm/networks/README.md

@@ -0,0 +1,51 @@
+# Custom EVM Networks
+
+The evm-networks crate defines custom network features that are shared across Foundry's tooling (`anvil`, `forge` and 
+`cast`). Currently, it supports custom precompiles, with planned support for custom transaction types.
+
+## Adding a Custom Network
+To add configuration support for a custom network (e.g. `my_network`), add a new field to the `NetworkConfigs` struct:
+```rust
+    /// Enable my custom network features.
+    #[arg(help_heading = "Networks", long)]
+    #[serde(default)]
+    pub my_network: bool,
+```
+This automatically enables::
+- `my_network = true` in foundry.toml
+- `--my-network` anvil CLI flag
+```
+Networks:
+      --my-network
+          Enable my custom network features
+
+```
+If you'd like network features to be enabled automatically based on the chain ID, update the implementation of:
+```rust
+impl NetworkConfigs {
+    pub fn with_chain_id(chain_id: u64) -> Self {
+        // Enable custom network features here
+    }
+}
+```
+
+## Adding a custom precompile
+
+- Create a module for your network-specific logic, e.g., `my_network/transfer`.
+- Implement the precompile logic as a function that accepts a `PrecompileInput` containing execution context and hooks for 
+interacting with EVM state, and returns a `PrecompileResult`:
+```rust
+pub fn custom_precompile(
+  input: alloy_evm::precompiles::PrecompileInput<'_>
+) -> revm::precompile::PrecompileResult {
+  // Your logic here
+}
+```
+- Enable the precompile in the `NetworkConfigs` implementation by conditionally applying it to an address:
+```rust
+if self.my_network {
+    precompiles.apply_precompile(&MY_NETWORK_TRANSFER_ADDRESS, move |_| {
+        Some(my_network::transfer::custom_precompile())
+    });
+}
+```

crates/evm/networks/src/lib.rs

@@ -27,11 +27,6 @@ pub struct NetworkConfigs {
 }
 
 impl NetworkConfigs {
-    pub fn celo(mut self, celo: bool) -> Self {
-        self.celo = celo;
-        self
-    }
-
     pub fn with_optimism() -> Self {
         Self { optimism: true, ..Default::default() }
     }