chore: baseline before change C-00001-setup-project

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/backlog.md

@@ -0,0 +1,40 @@
+# go-dns — Product Backlog
+
+Potential features for future change efforts. **Not a commitment** — items move into `docs/changes/` when scoped and prioritized.
+
+Align with [project-specification.md](project-specification.md): **`godns`** package, TSIG auth, typed RR builders, ASCII-only names, BIND testcontainer integration tests.
+
+**Priority legend:** P0 = core library, P1 = soon after core, P2 = enhancement, P3 = later / optional
+
+---
+
+## Zone transfer
+
+| Priority | Item |
+|----------|------|
+| P2 | **IXFR (incremental zone transfer)** — RFC 1995; apply deltas to a prior `Zone` snapshot; SOA serial baseline; fallback to AXFR when IXFR unavailable; extend `TransferResult` and BIND guide |
+
+---
+
+## Internationalization
+
+| Priority | Item |
+|----------|------|
+| P3 | **IDNA / punycode** — Unicode domain labels; normalization beyond ASCII-only validation |
+
+---
+
+## Record types & API
+
+| Priority | Item |
+|----------|------|
+| P2 | Additional typed RR builders beyond initial set (section 4 of setup spec) |
+| P3 | **Zone diff** helper — compare two `Zone` values for automation |
+
+---
+
+## Infrastructure
+
+| Priority | Item |
+|----------|------|
+| P3 | Example CLI or small tool wrapping `godns` (library remains primary deliverable) |