security: round 3 — token security (crypto random, hashed storage, portal middleware)

Token generation:
- Replace Str::ulid() with bin2hex(random_bytes(32)) for 256-bit entropy
- Store SHA-256 hash in database, never plaintext tokens
- Hash input before lookup on all token endpoints

Invitation tokens:
- InvitationService: generate crypto random, store hash, pass plain
  token transiently for email URL via UserInvitation::$plainToken
- InvitationController show/accept: hash input before DB lookup
- AcceptInvitationRequest: hash token before invitation lookup
- Migration: widen user_invitations.token and artists.portal_token
  from char(26) to char(64) for SHA-256 hex digests

Portal token auth:
- PortalTokenController: remove Schema::hasTable() runtime checks,
  hash token before lookup, return shaped response via PortalEventResource
  instead of raw model data
- Create PortalEventResource (name, dates, status only — no internals)
- Handle missing production_requests table gracefully via try/catch

Portal token middleware:
- Implement full token validation: extract from Bearer header or ?token=
  query param, hash, look up in artists/production_requests, verify
  event exists and is not draft/closed, set portal context on request
- Return generic 401 on any failure (no information leakage)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

api/app/Http/Controllers/Api/V1/InvitationController.php

@@ -39,7 +39,9 @@ final class InvitationController extends Controller
 
     public function show(string $token): JsonResponse
     {
-        $invitation = UserInvitation::where('token', $token)
+        $hashedToken = hash('sha256', $token);
+
+        $invitation = UserInvitation::where('token', $hashedToken)
             ->with(['organisation', 'invitedBy'])
             ->first();
 
@@ -52,7 +54,8 @@ final class InvitationController extends Controller
 
     public function accept(AcceptInvitationRequest $request, string $token): JsonResponse
     {
-        $invitation = UserInvitation::where('token', $token)->firstOrFail();
+        $hashedToken = hash('sha256', $token);
+        $invitation = UserInvitation::where('token', $hashedToken)->firstOrFail();
 
         $user = $this->invitationService->accept(
             $invitation,