fix(i18n): drop the orphaned backgroundTasks.runningList key

The strip rewrite removed its only call site, and an unreferenced key gets
promoted into the eagerly parsed boot catalog. Delete it from en.json and
regenerate en-runtime-required.json.

src/renderer/src/i18n/en-runtime-required.json

@@ -2610,9 +2610,6 @@
   },
   "components": {
     "native-chat": {
-      "backgroundTasks": {
-        "runningList": "Running background tasks"
-      },
       "composer": {
         "effort": "Effort"
       },

src/renderer/src/i18n/locales/en.json

@@ -17139,7 +17139,6 @@
         "command": "Background command",
         "monitor": "Background monitor",
         "task": "Background task",
-        "runningList": "Running background tasks",
         "detailsUnavailable": "Task details are unavailable for this session.",
         "countAgentsOne": "1 agent",
         "countAgentsMany": "{{value0}} agents",