feat: publish Dever core with project scaffolding and versioned AI skills

.trellis/tasks/09-20-port-adapter/implement.jsonl

@@ -0,0 +1,3 @@
+{"file":".trellis/spec/backend/compiler-contracts.md","reason":"Source role, visibility, failure and effect contracts"}
+{"file":".trellis/spec/backend/toolchain-and-library.md","reason":"Native dispatch, setting and official package boundary"}
+{"file":".trellis/spec/backend/database-guidelines.md","reason":"Transaction effect propagation and settings source"}