fix(WP-0014): pre-flight compilation fixes, Tailwind pipeline, and admin seed

A2 — Compilation fixes:
- Remove inline FK constraints from Schema.sql; IHP schema compiler cannot
  parse them. Add 1744329600-restore-fk-constraints.sql migration to restore
  referential integrity at the DB level.
- Rename `#label` → `#label_` throughout to avoid clash with Haskell built-in.
- Fix `hub.id == hid` UUID comparisons to use `toUUID hub.id`.
- Replace non-existent `setStatus`/`respondJson` calls with
  `renderJsonWithStatusCode` throughout Api controllers.
- Fix qualified package import for `cryptohash-sha256` in Auth.hs.
- Add `CanSelect (Text, Text)` instance in Helper.View.
- Refactor HSX inline lambdas to named helper functions in 100+ views
  (GHC cannot infer types for anonymous functions inside quasi-quoted HSX).
- Fix missing imports (IHP.QueryBuilder, IHP.Fetch, Web.Routes, Only, etc.)
  across helpers and controllers.
- Remove duplicate `diffUTCTime` definition in BottleneckDetector.
- Change `createEventForHub` return type from `IO ResponseReceived` to `IO ()`.
- Seed type-registry vocabulary via 1744502400-seed-type-registries.sql
  (moved from Schema.sql where IHP does not execute INSERT statements).

A3 — Tailwind build pipeline:
- Add `tailwindcss` to flake.nix native packages.
- Uncomment `tailwind.exec` process in devenv shell config.
- Add tailwind/tailwind.config.js (scans Web/View/**/*.hs).
- Add tailwind/app.css with @tailwind directives.

A4 — Admin user seed:
- Add 1744416000-seed-admin-user.sql: inserts admin@inter-hub.local
  with bcrypt-hashed password admin1234! (cost 10).
- Add .env.example documenting all required environment variables
  and default admin credentials.

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

Web/Controller/InteractionEvents.hs

@@ -4,8 +4,12 @@ import Web.Types
 import Generated.Types
 import IHP.Prelude
 import IHP.ControllerPrelude
-import Data.Aeson (object, (.=))
+import Data.Aeson (object, (.=), decode, Value)
+import qualified Data.Aeson as A
 import qualified Data.Text as T
+import qualified Data.ByteString.Lazy.Char8 as LBSC
+import IHP.Controller.Render (renderJson, renderJsonWithStatusCode)
+import Network.HTTP.Types (status422)
 
 -- Valid canonical event types
 validEventTypes :: [Text]
@@ -20,11 +24,7 @@ instance Controller InteractionEventsController where
     action CreateInteractionEventAction { widgetId } = do
         eventType <- param @Text "event_type"
         unless (eventType `elem` validEventTypes) do
-            respondJson (object ["error" .= ("unknown event_type" :: Text), "valid" .= validEventTypes])
-            -- IHP stops here; the above respondJson sends 200 but we need 422
-            -- Use renderWithStatus for proper 422:
-            setStatus 422
-            respondJson (object ["error" .= ("unknown event_type" :: Text)])
+            renderJsonWithStatusCode status422 (object ["error" .= ("unknown event_type" :: Text), "valid" .= validEventTypes])
 
         mUser <- currentUserOrNothing
         let actorId   = fmap (.id) mUser
@@ -34,20 +34,20 @@ instance Controller InteractionEventsController where
         viewContextRef <- paramOrNothing @Text "view_context_ref"
         metadataRaw    <- paramOrDefault @Text "{}" "metadata"
 
-        let metadata = case readMay @Value (cs metadataRaw) of
+        let metadata = case decode (LBSC.pack (cs metadataRaw)) of
                 Just v  -> v
-                Nothing -> object []
+                Nothing -> object [] :: A.Value
 
         event <- newRecord @InteractionEvent
             |> set #widgetId       widgetId
             |> set #eventType      eventType
-            |> set #actorId        (fmap (Id . unId) actorId)
+            |> set #actorId        (fmap toUUID actorId)
             |> set #actorType      actorTypeParam
             |> set #viewContextRef viewContextRef
             |> set #metadata       metadata
             |> createRecord
 
-        respondJson (object
+        renderJson (object
             [ "id"         .= event.id
             , "widget_id"  .= event.widgetId
             , "event_type" .= event.eventType