refactor: restructure packages, add Makefile for binding generation

.github/workflows/ci.yml

@@ -14,7 +14,8 @@ jobs:
       - name: Set up Go
         uses: actions/setup-go@v5
         with:
-          go-version: "1.25.6"
+          go-version-file: go.mod
+          cache-dependency-path: go.sum
 
       - name: Run Go tests
         run: go test ./...

.gitignore

@@ -0,0 +1,3 @@
+# Intermediate contract artifacts (generated by Makefile)
+custody/*.abi
+custody/*.bin

.gitmodules

@@ -3,4 +3,4 @@
 	url = https://github.com/foundry-rs/forge-std
 [submodule "contracts/evm/lib/openzeppelin-contracts"]
 	path = contracts/evm/lib/openzeppelin-contracts
-	url = https://github.com/OpenZeppelin/openzeppelin-contracts.git
+	url = https://github.com/OpenZeppelin/openzeppelin-contracts

Makefile

@@ -0,0 +1,24 @@
+SOL_SOURCES := $(shell find contracts/evm/src -name '*.sol')
+BINDINGS    := custody/iwithdraw.go custody/ideposit.go custody/simple_custody.go
+
+.PHONY: generate
+generate: $(BINDINGS)
+
+# Sentinel tracks forge build; only re-runs when .sol sources change.
+contracts/evm/out/.build-sentinel: $(SOL_SOURCES)
+	cd contracts/evm && forge build
+	@touch $@
+
+custody/iwithdraw.go: contracts/evm/out/.build-sentinel
+	jq .abi contracts/evm/out/IWithdraw.sol/IWithdraw.json > custody/IWithdraw.abi
+	abigen --abi custody/IWithdraw.abi --pkg custody --type IWithdraw --out $@
+
+custody/ideposit.go: contracts/evm/out/.build-sentinel
+	jq .abi contracts/evm/out/IDeposit.sol/IDeposit.json > custody/IDeposit.abi
+	abigen --abi custody/IDeposit.abi --pkg custody --type IDeposit --out $@
+
+custody/simple_custody.go: contracts/evm/out/.build-sentinel
+	jq .abi contracts/evm/out/SimpleCustody.sol/SimpleCustody.json > custody/SimpleCustody.abi
+	jq -r .bytecode.object contracts/evm/out/SimpleCustody.sol/SimpleCustody.json > custody/SimpleCustody.bin
+	abigen --abi custody/SimpleCustody.abi --bin custody/SimpleCustody.bin --pkg custody --type SimpleCustody --out $@
+