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

.trellis/tasks/archive/2026-10/09-20-large-cms-acceptance/check.jsonl

@@ -0,0 +1,3 @@
+{"file":".trellis/spec/backend/quality-guidelines.md","reason":"Focused CMS/compiler/runtime verification"}
+{"file":".trellis/spec/backend/directory-structure.md","reason":"No junk layers and dual-source ownership"}
+{"file":".trellis/spec/backend/error-handling.md","reason":"Business/API/Job failure flow review"}