fix(frontend): validate series_rules as array in settings parse/save

- Add Array.isArray() guard in parseSettings for series_rules, matching the existing EPG ignore list pattern
- Include series_rules in arrayFields list in getChangedSettings to prevent stringification during settings round-trip
- Add 5 tests covering valid, corrupted, and missing series_rules data

frontend/src/utils/pages/SettingsUtils.js

@@ -174,11 +174,12 @@ export const saveChangedSettings = async (settings, changedSettings) => {
 export const getChangedSettings = (values, settings) => {
   const changedSettings = {};
 
-  // EPG fields that should be kept as arrays
-  const epgFields = [
+  // Fields that must remain as arrays and not be stringified
+  const arrayFields = [
     'epg_match_ignore_prefixes',
     'epg_match_ignore_suffixes',
     'epg_match_ignore_custom',
+    'series_rules',
   ];
 
   for (const settingKey in values) {
@@ -199,12 +200,11 @@ export const getChangedSettings = (values, settings) => {
       continue;
     }
 
-    // Handle EPG fields specially - keep as arrays, don't skip empty arrays
-    if (epgFields.includes(settingKey)) {
+    // Handle array fields - keep as arrays, don't skip empty arrays
+    if (arrayFields.includes(settingKey)) {
       if (!Array.isArray(actualValue)) {
         actualValue = [];
       }
-      // Always include EPG fields in changes (even if empty)
       changedSettings[settingKey] = actualValue;
       continue;
     }
@@ -299,7 +299,9 @@ export const parseSettings = (settings) => {
       typeof dvrSettings.post_offset_minutes === 'number'
         ? dvrSettings.post_offset_minutes
         : parseInt(dvrSettings.post_offset_minutes, 10) || 0;
-    parsed.series_rules = dvrSettings.series_rules;
+    parsed.series_rules = Array.isArray(dvrSettings.series_rules)
+      ? dvrSettings.series_rules
+      : [];
   }
 
   // Backup settings - direct mapping with underscore keys

frontend/src/utils/pages/__tests__/SettingsUtils.test.js

@@ -328,6 +328,51 @@ describe('SettingsUtils', () => {
       const result = SettingsUtils.parseSettings(mockSettings);
       expect(result.network_access).toEqual(['192.168.1.0/24', '10.0.0.0/8']);
     });
+
+    it('should parse valid series_rules as array', () => {
+      const mockSettings = {
+        dvr_settings: {
+          id: 2,
+          key: 'dvr_settings',
+          value: {
+            series_rules: [{ tvg_id: 'abc', mode: 'all', title: 'Show' }],
+          },
+        },
+      };
+
+      const result = SettingsUtils.parseSettings(mockSettings);
+      expect(result.series_rules).toEqual([
+        { tvg_id: 'abc', mode: 'all', title: 'Show' },
+      ]);
+    });
+
+    it('should default series_rules to empty array when not an array', () => {
+      const mockSettings = {
+        dvr_settings: {
+          id: 2,
+          key: 'dvr_settings',
+          value: {
+            series_rules: 'corrupted',
+          },
+        },
+      };
+
+      const result = SettingsUtils.parseSettings(mockSettings);
+      expect(result.series_rules).toEqual([]);
+    });
+
+    it('should default series_rules to empty array when missing', () => {
+      const mockSettings = {
+        dvr_settings: {
+          id: 2,
+          key: 'dvr_settings',
+          value: {},
+        },
+      };
+
+      const result = SettingsUtils.parseSettings(mockSettings);
+      expect(result.series_rules).toEqual([]);
+    });
   });
 
   describe('getChangedSettings', () => {
@@ -447,6 +492,23 @@ describe('SettingsUtils', () => {
       expect(changes.epg_match_ignore_suffixes).toEqual([]);
       expect(changes.epg_match_ignore_custom).toEqual([]);
     });
+
+    it('should keep series_rules as array and not stringify', () => {
+      const rules = [{ tvg_id: 'abc', mode: 'all', title: 'Show' }];
+      const values = { series_rules: rules };
+      const settings = {};
+
+      const changes = SettingsUtils.getChangedSettings(values, settings);
+      expect(changes.series_rules).toEqual(rules);
+    });
+
+    it('should default series_rules to empty array if not an array', () => {
+      const values = { series_rules: 'corrupted' };
+      const settings = {};
+
+      const changes = SettingsUtils.getChangedSettings(values, settings);
+      expect(changes.series_rules).toEqual([]);
+    });
   });
 
   describe('saveChangedSettings - EPG Mode', () => {