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/Support/Presence.php

@@ -0,0 +1,73 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Support;
+
+use App\Models\User;
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Support\Collection;
+use Illuminate\Support\Facades\Cache;
+
+/**
+ * Who else has a record's edit screen open right now.
+ *
+ * Advisory, not authoritative — there is no signal at all for "closed the
+ * tab", so presence really means "opened this within the last few minutes",
+ * which fades out on its own once nobody touches the screen again. That
+ * heuristic is the right shape for the problem: knowing that two people are
+ * mid-edit matters; an exact headcount does not.
+ */
+final class Presence
+{
+    /**
+     * How long somebody stays "here" after they were last seen. Long enough
+     * to survive reading a long field without typing; short enough that a
+     * closed tab does not haunt a record for the rest of the day.
+     */
+    protected const TTL_MINUTES = 10;
+
+    /**
+     * Record this user as here now, and answer who else already was.
+     *
+     * Reading and writing happen in one call because that is the one moment
+     * presence is ever needed: opening the screen. There is no separate
+     * "who is here" query anywhere else, so there is nothing for the two to
+     * disagree about.
+     *
+     * @return Collection<int, User>
+     */
+    public static function touch(Model $record, User $user): Collection
+    {
+        $key = self::key($record);
+        $cutoff = now()->subMinutes(self::TTL_MINUTES)->timestamp;
+
+        $present = collect(self::entries($key))
+            ->filter(fn (int $seenAt) => $seenAt >= $cutoff);
+
+        // Answered before this visit is recorded: nobody is ever told they
+        // are keeping themselves company.
+        $others = $present->keys()->reject(fn (int $id) => $id === $user->getKey());
+
+        $present[$user->getKey()] = now()->timestamp;
+
+        Cache::put($key, $present->all(), now()->addMinutes(self::TTL_MINUTES));
+
+        return $others->isEmpty()
+            ? collect()
+            : User::query()->whereKey($others)->get();
+    }
+
+    protected static function key(Model $record): string
+    {
+        return 'presence:'.$record->getMorphClass().':'.$record->getKey();
+    }
+
+    /**
+     * @return array<int, int>
+     */
+    protected static function entries(string $key): array
+    {
+        return (array) Cache::get($key, []);
+    }
+}