canon: distinguish sector domains from project identity

canon/standards/repo-classification-standard_v1.0.md

@@ -388,6 +388,24 @@ secondary_domains:
 | `space` | Space industry, satellites, orbital systems, launch, space logistics, space simulation. |
 | `government` | B2G, civic infrastructure, public administration, procurement, citizen services, regulation-facing systems. |
 
+### 6.3 Legacy Project Identities Are Not Domain Aliases
+
+The older labels `custodian`, `railiance`, `markitect`, `coulomb_social`,
+`personhood`, `foerster_capabilities`, and `netkingdom` identify projects,
+estates, or bodies of canon. They are not allowed values for
+`repo_classification.domain` and MUST NOT be mechanically translated as if
+each named project served one market sector.
+
+Keep those identities in project titles, topics, architecture, provenance,
+and historical records. Classify each repository by the user/customer rule in
+§6.1. A project can legitimately contain repos in different sectors: for
+example, a Railiance platform repo can be `infotech`, while a rail-operations
+product can be `industrials`.
+
+Migration review seeds and the live 2026-08-23 fleet baseline are recorded in
+`docs/repo-classification-sector-migration-baseline-2026-08-23.md`. Its mapping
+table is a triage aid, not an automatic rewrite rule.
+
 ---
 
 ## 7. Capability Tags