Add configurable distribution supply types

AGENTS.md

@@ -283,17 +283,23 @@ that have remained unchanged. ProjectDevice create, update, delete and
 global-to-project copy API/UI paths use these persistent commands and track the
 returned project revision. ProjectDevice synchronization/disconnect API and UI
 paths do the same; their undo action uses the project-wide history endpoint.
-Project voltage settings use the persistent `project.update-settings` command.
-Both voltage defaults change in one revision and Undo/Redo restores them
-together; the project PUT route requires `expectedRevision`.
+Project settings use the persistent `project.update-settings` command. Project
+metadata, both voltage defaults and the enabled distribution-board supply types
+change in one revision and Undo/Redo restores them together; the project PUT
+route requires `expectedRevision`. The system catalog is `AV`, `SV`, `EV`,
+`USV`, `MSR`, `SiBe`; at least one must be enabled and a type used by a board
+cannot be disabled.
 Distribution-board setup uses `distribution-board.insert` with a complete
 stable snapshot of the board, circuit list and four default sections. Its
 inverse removes only the same unchanged and still-empty structure; the POST
 route requires `expectedRevision` and returns the updated history state.
+Distribution-board floor assignment and a project-enabled supply type use
+`distribution-board.update`; both values are snapshot/export fields and one
+persistent undo step.
 Floor and room setup use `project-floor.insert` and `project-room.insert` with
 complete stable snapshots. Their inverses remove only unchanged records and
-reject floors with assigned rooms or rooms referenced by device rows or
-retained upgrade data. Both POST routes require `expectedRevision` and return
+reject floors with assigned rooms/distribution boards or rooms referenced by
+device rows or retained upgrade data. Both POST routes require `expectedRevision` and return
 the updated history state.
 
 Required operations: