feat(ui): wählbares Listen-Icon und aufgeräumter Task-Detail-Header

Listen bekommen eine Icon-Spalte (Migration AddListIcon) und einen Icon-Picker
in den Listeneinstellungen; 34 kuratierte Geometrien aus der Icon-Bibliothek,
Fallback auf "Folder" bei unbekanntem Key.

Der Metadata-Footer im Task-Detail entfällt; created-at wandert in die
Header-Zeile neben das ID-Badge, der Close-Button (und CloseDetailsCommand)
fällt weg.

src/ClaudeDo.Localization/locales/en.json

@@ -261,7 +261,6 @@
     "killSessionTip": "Kill the running session",
     "sendToQueue": "Send to queue",
     "sendToQueueTip": "Queue this task so Claude picks it up on the next run",
-    "closeTip": "Close",
     "copyTaskIdTip": "Copy task ID",
     "starTip": "Star",
     "agentSettingsTip": "Agent settings",
@@ -396,6 +395,9 @@
       "manualListHint": "New tasks in this list start out manual: no queueing, running or refining, and automation skips them. You can still open a hand-driven session.",
       "findingsTracked": "Commit the .claudedo findings folder",
       "findingsTrackedHint": "Off: the folder stays out of git via .git/info/exclude. On: findings travel with the repo.",
+      "sectionIcon": "ICON",
+      "icon": "List icon",
+      "iconHint": "Shown next to the list name in the sidebar.",
       "sectionAgent": "AGENT",
       "resetAgentSettings": "Reset agent settings",
       "sectionVerify": "VERIFICATION",