Add contract placeholder, ignore non placeholder contract

Author: MoonBoi9001

.gitignore

@@ -10,6 +10,8 @@ data/
 postgres_data/
 logs/
 subgraph/
+
+# Ignore real contract files but allow placeholders
 contracts/contract.abi.json
 
 # Ignore Ruff

contracts/placeholder.abi.json

@@ -0,0 +1 @@
+{"placeholder": "This is a placeholder ABI file for CI/CD builds"}