fix: login/signup flow working with session-based auth

- Fixed hashPasswordIO to use real PBKDF2 hashing from Sis.Auth
- Added seed route (rseed) for demo data initialization
- Replaced redirect() in update functions with success views
  (redirect uses throwError_ which broke with effectful 2.4)
- Added loginSuccessView and signupSuccessView with dashboard links
- Patched Hyperbole Socket.hs to parse WebSocket form body into Form params
- Patched Hyperbole Wai.hs to include TargetViewId in response metadata
- Fixed View/Page type mismatches (hyper wrapper vs plain view)
- Removed dead pure after redirect calls
- Verified: login submits, session set, success view rendered

src/Sis/Page/Activity.hs

@@ -98,7 +98,7 @@ page = do
     case mSession of
         Nothing -> do
             redirect (routeUri RLogin)
-            pure $ hyper ActivityPage $ el "Redirecting..."
+
         Just us -> do
             hhs <- getUserHouseholds (UserId (usUserId us))
             case hhs of