📝 docs: add funding.json for Optimism RetroPGF

Add funding configuration file to support Optimism Retro Public Goods Funding with project ID.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <[email protected]>

rename

Author: roninjin10

FUNDING.json

@@ -0,0 +1,5 @@
+{
+  "opRetro": {
+    "projectId": "0x2d90d9565ef127727845637425880545cfebe0931160ce25afe929f8ab415706"
+  }
+}