Enhance XEPG channel mapping and settings management

html/lang/en.json

@@ -399,6 +399,13 @@
       "title": "Replace missing program images",
       "description": "If the poster in the XMLTV program is missing, the channel logo will be used."
     },
+    "xepgMissingEPGMode":
+    {
+      "title": "Missing EPG Handling",
+      "description": "Strict: channels are deactivated when XMLTV mappings disappear.<br>Relaxed: channels stay active with last-known mappings and fall back to a dummy guide whenever guide data cannot be resolved.",
+      "info_strict": "Strict (deactivate channels)",
+      "info_relaxed": "Relaxed (keep active / dummy guide)"
+    },
     "xteveAutoUpdate":
     {
       "title": "Automatic update of xTeVe",