feat(mission-control): give the list handler its own review task

"Let Claude handle it" now creates one ClaudeDo task per run to host the
ConPTY session (Idle/IsManual, never queued) instead of an untracked
ad-hoc tile, so the run has a real title, diff, and review outcome.
Since the handler merges its own changes straight into the list's
working dir, the task never gets a WorktreeEntity; its review range
lives as new HandlerBaseCommit/HandlerHeadCommit columns on TaskEntity
instead, reusing the existing commit-range diff machinery and keeping
it out of the worktrees overview entirely.

src/ClaudeDo.Localization/locales/en.json

@@ -284,6 +284,8 @@
     "conptyLaunchFailed": "Couldn't open ConPTY session: {0}",
     "conptyStarting": "Starting session…",
     "mergeHelperTitle": "Merge Helper",
+    "mergeHelperTaskTitle": "List handler: {0}",
+    "mergeHelperTaskDescriptionHeader": "Tasks handled by this run:",
     "submitForReviewFailed": "Couldn't submit for review: {0}",
     "submitForReview": "Submit for review",
     "submitForReviewTip": "Commit this worktree and move the task to review so it can be merged",