feat(daily-prep): trigger planning from inside the prep-log window with an empty-state hint

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

src/ClaudeDo.Localization/locales/en.json

@@ -66,7 +66,6 @@
     "addPlaceholder": "Add a task…",
     "enterKey": "ENTER",
     "notesPinnedRow": "Notes (daily notes)",
-    "prepareDay": "Prepare day",
     "clearDayTip": "Clear day",
     "prepLogTip": "Prep log",
     "overdue": "OVERDUE",
@@ -140,7 +139,9 @@
     "previewBtn": "Preview",
     "editBtn": "Edit",
     "descriptionPlaceholder": "Add task details (markdown supported)...",
-    "prepTitle": "Daily prep"
+    "prepTitle": "Daily prep",
+    "planDay": "Plan day",
+    "prepEmpty": "No prep run today yet — click Plan day"
   },
   "agent": {
     "stopTip": "Stop agent",