v0.5.4: monitoring page frontend fixes

- Fix tooltip "Invalid Date" by using raw.x with parsed.x fallback
- Fix chart x-axis bounds by including initial min/max in chartOpts
- Fix sysinfo alignment with fixed 2-column grid and consistent styling
- Fix chart overflow on mobile with min-width:0 and overflow:hidden
- Remove redundant <style> block from monitoring.html (moved to style.css)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

controller/internal/web/templates/monitoring.html

@@ -1,14 +1,6 @@
 {{define "monitoring"}}
 {{template "layout_start" .}}
 
-<style>
-/* Monitoring page specific overrides */
-.sysinfo-value {
-    text-align: right;
-    font-weight: bold;
-}
-</style>
-
 <div class="page-header">
     <h2>Rendszermonitor</h2>
 </div>
@@ -183,6 +175,8 @@
 
     // --- Chart options for line charts with LINEAR x-axis ---
     function chartOpts(yLabel, beginAtZero) {
+        var now = Date.now();
+        var defaultRangeMs = parseRangeMs('1h');
         return {
             responsive: true,
             maintainAspectRatio: false,
@@ -198,8 +192,14 @@
                     callbacks: {
                         title: function(items) {
                             if (!items.length) return '';
-                            // parsed.x is the ms timestamp on a linear axis
-                            return formatTimestamp(items[0].parsed.x);
+                            var raw = items[0].raw;
+                            if (raw && typeof raw === 'object' && raw.x) {
+                                return formatTimestamp(raw.x);
+                            }
+                            if (items[0].parsed && items[0].parsed.x) {
+                                return formatTimestamp(items[0].parsed.x);
+                            }
+                            return '';
                         }
                     }
                 }
@@ -207,6 +207,8 @@
             scales: {
                 x: {
                     type: 'linear',
+                    min: now - defaultRangeMs,
+                    max: now,
                     grid: {color: 'rgba(48,54,61,0.5)'},
                     ticks: {
                         color: '#8b949e',