Add job logging and increase timeout to 20 minutes

- Add JobLogger class to handler.py for structured timestamped logging
- Increase MAX_TIMEOUT from 600s to 1200s (20 minutes)
- Add logs column to generated_content table via migration
- Store and display job execution logs in gallery UI
- Add Logs button to gallery items with modal display

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/public/css/style.css

@@ -766,3 +766,65 @@ body {
     text-shadow: 0 1px 3px rgba(0,0,0,0.5);
     pointer-events: none;
 }
+
+/* Logs Modal */
+.logs-container {
+    background: var(--gray-100);
+    border-radius: var(--radius);
+    padding: 15px;
+}
+
+.logs-status {
+    margin-bottom: 12px;
+    font-size: 14px;
+}
+
+.logs-status .badge {
+    margin-left: 8px;
+}
+
+.badge-completed { background: var(--success); color: white; }
+.badge-processing { background: var(--warning); color: var(--gray-900); }
+.badge-pending { background: var(--gray-500); color: white; }
+.badge-failed { background: var(--danger); color: white; }
+
+.logs-error {
+    background: #f8d7da;
+    color: #721c24;
+    padding: 12px;
+    border-radius: var(--radius);
+    margin-bottom: 12px;
+    font-size: 13px;
+}
+
+.logs-content {
+    font-family: 'SF Mono', Monaco, 'Andale Mono', monospace;
+    font-size: 12px;
+    line-height: 1.6;
+    background: var(--gray-900);
+    color: #e0e0e0;
+    padding: 15px;
+    border-radius: var(--radius);
+    max-height: 400px;
+    overflow-y: auto;
+    white-space: pre-wrap;
+    word-break: break-word;
+}
+
+.logs-content::-webkit-scrollbar {
+    width: 8px;
+}
+
+.logs-content::-webkit-scrollbar-track {
+    background: var(--gray-800);
+    border-radius: 4px;
+}
+
+.logs-content::-webkit-scrollbar-thumb {
+    background: var(--gray-600);
+    border-radius: 4px;
+}
+
+.logs-content::-webkit-scrollbar-thumb:hover {
+    background: var(--gray-500);
+}