feat(WP-0009): IHF GAAF Compliance Foundation — type registries, extension manifests, architectural contracts

Implements IHUB-WP-0009: closes four GAAF-2026 gaps before domain hub work begins.
- TypeRegistry helper + controllers/views (hub_kind, hub_capability_manifest)
- HubCapabilityManifest entity with validation and registry linkage
- ARCHITECTURE-LAYERS.md + CI-enforced boundary contracts
- Alembic migration 1743724800, fitness tests (Test/Architecture/)
- GAAF spec, Operational Architecture spec, domain hub extension guide
- Updates to CLAUDE.md, SCOPE.md, Schema.sql, Routes, FrontController, Types

state_hub_sync: pending (tunnel was STALE at completion time; run fix-consistency)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Web/Controller/ApiInteractionEvents.hs

@@ -7,10 +7,7 @@ import IHP.ControllerPrelude
 import Data.Aeson (object, (.=))
 import qualified Data.Text as T
 import Network.Wai (requestMethod, requestHeaders)
-
--- | Accepted event types per InteractionReportingContract v1.0
-apiAcceptedEventTypes :: [Text]
-apiAcceptedEventTypes = ["clicked", "viewed", "submitted", "dismissed", "errored"]
+import Application.Helper.TypeRegistry (validateEventType)
 
 instance Controller ApiInteractionEventsController where
 
@@ -65,12 +62,15 @@ createEventForHub hub = do
     let Just wIdText = widgetIdText
         Just evType  = eventType
 
-    unless (evType `elem` apiAcceptedEventTypes) do
-        setStatus 422
-        respondJson (object
-            [ "error"    .= ("Unacceptable event_type" :: Text)
-            , "accepted" .= apiAcceptedEventTypes
-            ])
+    evTypeResult <- liftIO $ validateEventType evType
+    case evTypeResult of
+        Left _ -> do
+            setStatus 422
+            respondJson (object
+                [ "error"    .= ("Unacceptable event_type" :: Text)
+                , "hint"     .= ("Register the event type in the Type Registry before submitting" :: Text)
+                ])
+        Right () -> pure ()
 
     -- Resolve widget — must belong to this hub.
     case readMay wIdText of