Initial commit: Pireon Admin — headless admin panel and public API

Laravel 13 + Filament 5 admin panel and REST API for a non-profit developer
collective, backed by the Pireon OAuth identity server. The public site is a
separate, server-rendered application consuming /api/public/v1.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

app/Models/Revision.php

@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Attributes\Fillable;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
+
+/**
+ * One recorded change to one record.
+ *
+ * Keeps the author's name as well as the link to their account: people leave,
+ * accounts get deleted, and "somebody published this in March" is worth less
+ * than a name.
+ */
+#[Fillable(['user_id', 'user_name', 'event', 'changeset'])]
+class Revision extends Model
+{
+    public const UPDATED_AT = null;
+
+    protected function casts(): array
+    {
+        return ['changeset' => 'array'];
+    }
+
+    /**
+     * @return MorphTo<Model, $this>
+     */
+    public function revisionable(): MorphTo
+    {
+        return $this->morphTo();
+    }
+
+    /**
+     * @return BelongsTo<User, $this>
+     */
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    public function author(): string
+    {
+        // The live name when the account is at hand — people rename
+        // themselves — and the recorded one otherwise, including once the
+        // account is gone. Never a lazy load: this is read inside table rows.
+        if ($this->relationLoaded('user') && $this->user !== null) {
+            return $this->user->name;
+        }
+
+        return $this->user_name ?? __('panel.revisions.system');
+    }
+
+    /**
+     * The attributes this revision touched.
+     *
+     * @return array<int, string>
+     */
+    public function fields(): array
+    {
+        return array_keys($this->changeset ?? []);
+    }
+
+    /**
+     * What a given attribute looked like before and after.
+     *
+     * @return array{old: mixed, new: mixed}
+     */
+    public function diff(string $field): array
+    {
+        return [
+            'old' => $this->changeset[$field]['old'] ?? null,
+            'new' => $this->changeset[$field]['new'] ?? null,
+        ];
+    }
+
+    /**
+     * The values needed to put a record back the way it was.
+     *
+     * @return array<string, mixed>
+     */
+    public function previousValues(): array
+    {
+        return collect($this->changeset ?? [])
+            ->map(fn (array $change) => $change['old'] ?? null)
+            ->all();
+    }
+}