Add central Audit Trail viewer in Filament admin

Features:
- AuditResource with table listing all audit logs
- ViewAudit page showing detailed changes with diff table
- Filters: date range, user, model type, event type
- Search by user name
- Auto-refresh every 60 seconds
- Dark mode support for changes view
- Fixed audits migration with proper schema
- Added audit.view permission (admin only by default)

Files:
- src/app/Models/Audit.php
- src/app/Filament/Resources/AuditResource.php
- src/app/Filament/Resources/AuditResource/Pages/
- src/resources/views/filament/infolists/entries/audit-changes.blade.php
- Updated audits migration with full schema

src/app/Models/Audit.php

@@ -0,0 +1,111 @@
+<?php
+
+namespace App\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+use Illuminate\Database\Eloquent\Relations\MorphTo;
+
+class Audit extends Model
+{
+    protected $table = 'audits';
+
+    protected $guarded = [];
+
+    protected $casts = [
+        'old_values' => 'array',
+        'new_values' => 'array',
+    ];
+
+    /**
+     * Get the user that performed the action.
+     */
+    public function user(): BelongsTo
+    {
+        return $this->belongsTo(User::class);
+    }
+
+    /**
+     * Get the auditable model.
+     */
+    public function auditable(): MorphTo
+    {
+        return $this->morphTo();
+    }
+
+    /**
+     * Get the event badge color.
+     */
+    public function getEventColorAttribute(): string
+    {
+        return match ($this->event) {
+            'created' => 'success',
+            'updated' => 'warning',
+            'deleted' => 'danger',
+            'restored' => 'info',
+            default => 'gray',
+        };
+    }
+
+    /**
+     * Get a human-readable model name.
+     */
+    public function getModelNameAttribute(): string
+    {
+        $class = class_basename($this->auditable_type);
+        return preg_replace('/(?<!^)[A-Z]/', ' $0', $class);
+    }
+
+    /**
+     * Get formatted changes for display.
+     */
+    public function getFormattedChangesAttribute(): array
+    {
+        $changes = [];
+        $oldValues = $this->old_values ?? [];
+        $newValues = $this->new_values ?? [];
+
+        $allKeys = array_unique(array_merge(array_keys($oldValues), array_keys($newValues)));
+
+        foreach ($allKeys as $key) {
+            $old = $oldValues[$key] ?? null;
+            $new = $newValues[$key] ?? null;
+
+            if ($old !== $new) {
+                $changes[] = [
+                    'field' => $key,
+                    'old' => $this->formatValue($old),
+                    'new' => $this->formatValue($new),
+                ];
+            }
+        }
+
+        return $changes;
+    }
+
+    /**
+     * Format a value for display.
+     */
+    protected function formatValue($value): string
+    {
+        if (is_null($value)) {
+            return '(empty)';
+        }
+
+        if (is_bool($value)) {
+            return $value ? 'Yes' : 'No';
+        }
+
+        if (is_array($value)) {
+            return json_encode($value);
+        }
+
+        $stringValue = (string) $value;
+        
+        if (strlen($stringValue) > 100) {
+            return substr($stringValue, 0, 100) . '...';
+        }
+
+        return $stringValue;
+    }
+}