fix(ui): remove duplicate Let-Claude entry point and icon collision

Context-menu "Let Claude handle it" on list rows duplicated the header
button; both routed to the same ListsIslandViewModel command via the
shell, so only the context menu entry (and its now-unused locale key)
is removed. The header button also shared Icon.Broom with Clear Day —
gave it Icon.AgentSuggested instead.

src/ClaudeDo.Localization/locales/de.json

@@ -194,7 +194,6 @@
     "contextWorktrees": "Worktrees…",
     "contextOpenExplorer": "Im Explorer öffnen",
     "contextOpenTerminal": "Im Terminal öffnen",
-    "contextLetClaude": "Claude machen lassen",
     "newList": "Neue Liste",
     "addReposTip": "Repos als Listen hinzufügen"
   },

src/ClaudeDo.Localization/locales/en.json

@@ -194,7 +194,6 @@
     "contextWorktrees": "Worktrees…",
     "contextOpenExplorer": "Open in Explorer",
     "contextOpenTerminal": "Open in Terminal",
-    "contextLetClaude": "Let Claude handle it",
     "newList": "New list",
     "addReposTip": "Add repos as lists"
   },