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

.trellis/tasks/09-20-secure-data-contracts/check.jsonl

@@ -0,0 +1,3 @@
+{"file":".trellis/spec/backend/quality-guidelines.md","reason":"Focused compiler/runtime test selection"}
+{"file":".trellis/spec/backend/error-handling.md","reason":"Typed crypto failure and diagnostic rules"}
+{"file":".trellis/spec/backend/directory-structure.md","reason":"Single owner across checker, emitter and runtime"}