fix(register): require explicit topic when ambiguous

Assistant: codex
Assistant-Model: gpt-5.6-sol
Assistant-Session: 01a06d83-1cbc-71f2-b0dc-e0f48cedae43

workplans/ADHOC-2026-09-04.md

@@ -0,0 +1,34 @@
+---
+id: STATE-WP-ADHOC-2026-09-04
+type: workplan
+title: "Ad hoc fixes — 2026-09-04"
+domain: infotech
+repo: state-hub
+status: finished
+owner: codex
+topic_slug: state-hub
+created: "2026-09-04"
+updated: "2026-09-04"
+---
+
+## Add explicit topic selection to statehub register
+
+```task
+id: STATE-WP-ADHOC-2026-09-04-T01
+status: done
+priority: high
+```
+
+Add a `--topic` option that selects an existing active topic by slug within the
+chosen domain. Refuse missing, cross-domain, or ambiguous topic selection rather
+than silently assigning the first active topic in the domain. Preserve the
+single-topic fallback and exact inferred-topic selection for compatibility.
+
+Completed 2026-09-04. `statehub register --domain <domain> --topic <slug>` now
+selects the exact active topic and propagates its UUID to generated files, the
+repository registration/update, and the progress receipt. An explicit missing
+or cross-domain slug fails with a targeted error. Without `--topic`, an exact
+inference match wins, a sole domain topic remains backward-compatible, and an
+ambiguous domain now requires an explicit choice. Focused registration tests
+pass (`26 passed`); the full suite passes (`835 passed`, one pre-existing
+SQLAlchemy warning). Source distribution and wheel builds succeed.