Add configurable minimum refresh interval setting

Added user-configurable minimum refresh interval for inventory reloads, allowing users to control how frequently the maintenance service triggers updates (default: 30 minutes, range: 1-1440 minutes).

- Add minimum_refresh_interval_minutes to settings system with default of 30 minutes
- Update maintenance service to use configurable interval instead of hardcoded 1-minute value
- Add GUI input field in General Settings with auto-save functionality
- Include field in API settings endpoint and settings manager

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

web/index.html

@@ -112,6 +112,10 @@
                         Connection Quality:
                         <input type="number" id="connection-quality" min="1" max="6" value="1">
                     </label>
+                    <label>
+                        Minimum Refresh Interval (minutes):
+                        <input type="number" id="minimum-refresh-interval" min="1" max="1440" value="30">
+                    </label>
                 </section>
 
                 <section class="settings-section">

web/static/app.js

@@ -540,6 +540,7 @@ function updateSettingsUI(settings) {
     state.settings = settings;
     document.getElementById('dark-mode').checked = settings.dark_mode || false;
     document.getElementById('connection-quality').value = settings.connection_quality || 1;
+    document.getElementById('minimum-refresh-interval').value = settings.minimum_refresh_interval_minutes || 30;
 
     if (settings.dark_mode) {
         document.body.classList.add('dark-mode');
@@ -861,6 +862,7 @@ async function saveSettings() {
     const settings = {
         dark_mode: document.getElementById('dark-mode').checked,
         connection_quality: parseInt(document.getElementById('connection-quality').value),
+        minimum_refresh_interval_minutes: parseInt(document.getElementById('minimum-refresh-interval').value),
         games_to_watch: state.settings.games_to_watch || []
     };
 
@@ -928,6 +930,7 @@ document.addEventListener('DOMContentLoaded', () => {
         saveSettings();
     });
     document.getElementById('connection-quality').addEventListener('change', saveSettings);
+    document.getElementById('minimum-refresh-interval').addEventListener('change', saveSettings);
     document.getElementById('reload-btn').addEventListener('click', reloadCampaigns);
 
     // Games to watch management