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/Resources/Api/V1/PortalEventResource.php

@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Http\Resources\Api\V1;
+
+use Illuminate\Http\Request;
+use Illuminate\Http\Resources\Json\JsonResource;
+
+final class PortalEventResource extends JsonResource
+{
+    public function toArray(Request $request): array
+    {
+        return [
+            'id' => $this->id,
+            'name' => $this->name,
+            'slug' => $this->slug,
+            'start_date' => $this->start_date?->toDateString(),
+            'end_date' => $this->end_date?->toDateString(),
+            'status' => $this->status,
+            'event_type' => $this->event_type,
+        ];
+    }
+}