Fix DebugBar production crash and guard Database instrumentation

DebugBar used self:: in heredoc causing undefined variable fatal error.
Database query instrumentation now wrapped in try/catch so logging/debug
can never crash actual queries.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/Core/Database.php

@@ -41,6 +41,7 @@ class Database
         $stmt->execute($params);
         $elapsed = microtime(true) - $start;
 
+        try {
             DebugBar::recordQuery($elapsed);
 
             if ($elapsed > 0.1) {
@@ -54,6 +55,8 @@ class Database
                     Logger::warning("N+1 detected: table '{$table}' queried 11+ times in single request");
                 }
             }
+        } catch (\Throwable $e) {
+        }
 
         return $stmt;
     }

app/Core/DebugBar.php

@@ -5,7 +5,7 @@ namespace App\Core;
 
 final class DebugBar
 {
-    private static float $startTime;
+    private static float $startTime = 0;
     private static int $queryCount = 0;
     private static float $queryTime = 0.0;
 
@@ -22,13 +22,12 @@ final class DebugBar
 
     public static function render(): string
     {
-        $totalTime = round((microtime(true) - self::$startTime) * 1000);
+        $totalTime = self::$startTime > 0 ? round((microtime(true) - self::$startTime) * 1000) : 0;
         $memory = round(memory_get_peak_usage(true) / 1024 / 1024, 1);
+        $queryCount = self::$queryCount;
         $queryTime = round(self::$queryTime * 1000);
 
         $app = App::getInstance();
-        $route = '-';
-        $permission = '-';
         $employee = '-';
 
         try {
@@ -43,7 +42,7 @@ final class DebugBar
         <div id="debug-bar" style="position:fixed;bottom:0;left:0;right:0;background:#1a1a2e;color:#e0e0e0;font-family:monospace;font-size:11px;padding:6px 15px;z-index:99999;direction:ltr;text-align:left;display:flex;gap:20px;align-items:center;border-top:2px solid #0D7377;">
             <span style="color:#4ecdc4;font-weight:bold;">DEBUG</span>
             <span>Time: <b>{$totalTime}ms</b></span>
-            <span>Queries: <b>{self::$queryCount}</b> ({$queryTime}ms)</span>
+            <span>Queries: <b>{$queryCount}</b> ({$queryTime}ms)</span>
             <span>Memory: <b>{$memory}MB</b></span>
             <span>Employee: <b>{$employee}</b></span>
         </div>