feat(merge): Stash-Option fuer uncommittete Aenderungen im Ziel-Tree

Ein dirty Ziel-Arbeitsverzeichnis gibt jetzt den eigenen Status
dirty_target zurueck statt blocked. Die UI bietet daraufhin einen
Retry an, der per git merge --autostash stasht, merged und die
Aenderungen danach wiederherstellt - opt-in pro Merge:

- Approve & Merge: Bestaetigungsdialog
- Merge-Modal: Button "Aenderungen stashen und mergen"
- MCP (merge_task/review_task) wirft weiterhin, kein autostash dort

src/ClaudeDo.Localization/locales/en.json

@@ -481,7 +481,8 @@
       "targetBranch": "Target branch",
       "removeWorktree": "Remove worktree after merge",
       "commitMessage": "Commit message",
-      "conflictedFiles": "Conflicted files:"
+      "conflictedFiles": "Conflicted files:",
+      "stashAndMerge": "Stash changes and merge"
     },
     "diff": {
       "title": "DIFF",
@@ -850,7 +851,7 @@
     "tasksIsland": { "completedHeader": "COMPLETED", "completedHeaderCount": "COMPLETED · {0}", "statusPill": "{0} running · {1} review", "openTaskOne": "1 open task", "openTasks": "{0} open tasks", "planningResumeFailed": "Couldn't resume planning session: {0}", "approveFailed": "Approve & merge failed: {0}", "cancelReviewFailed": "Cancel review failed: {0}", "sendToQueueFailed": "Send to queue failed: {0}", "queuePlanBlockedInteractive": "Can't queue the plan — {0} has an open interactive session and must be closed first.", "moveRunningRejected": "Can't move a running task to another list.", "moveWorktreeRejected": "Can't move — this task has an active worktree pointing at its current repo.", "moveRepoConfirm": "Different repos — {0} → {1}. Move the task anyway?", "moveConfirmUnavailable": "Can't move — the confirmation dialog isn't available.", "quickClaudeNoWorkingDir": "This list has no working directory configured.", "quickClaudeDirMissing": "Working directory no longer exists: {0}", "setStatusFailed": "Failed to update status: {0}", "cancelFailed": "Cancel failed: {0}", "rejectToQueueFailed": "Reject to queue failed: {0}", "rejectToIdleFailed": "Reject failed: {0}", "deleteTaskConfirm": "Delete \"{0}\"? This cannot be undone.", "deleteTaskFailed": "Delete failed: {0}", "toggleDoneFailed": "Couldn't update done state: {0}", "removeFromQueueFailed": "Remove from queue failed: {0}", "openWorktreeFailed": "Couldn't open worktree: {0}" },
     "diff": { "loadFailed": "Failed to load diff: {0}", "noChanges": "No changes to show.", "unavailable": "Diff no longer available — commit range incomplete." },
     "planningDiff": { "hubError": "Could not build combined preview (hub error).", "conflict": "Cannot build combined preview: subtask {0} conflicts with an earlier subtask ({1} files).", "buildFailed": "Could not build combined preview: {0}" },
-    "merge": { "commitMessage": "chore: merge {0}", "progressMerging": "Merging…", "progressVerifying": "Running the list's verify command… ({0})", "workerOfflineBranches": "Worker offline — cannot list branches.", "loadBranchesFailed": "Failed to load branches: {0}", "merged": "Merged.", "blocked": "Blocked: {0}", "verifyFailed": "Merge landed, but the list's verify command failed — the task was kept out of Done.", "untrackedCollision": "Merge refused — it would overwrite an untracked file in the target working directory.", "unknownStatus": "Unknown status: {0}", "mergeFailed": "Merge failed: {0}" },
+    "merge": { "commitMessage": "chore: merge {0}", "progressMerging": "Merging…", "progressVerifying": "Running the list's verify command… ({0})", "workerOfflineBranches": "Worker offline — cannot list branches.", "loadBranchesFailed": "Failed to load branches: {0}", "merged": "Merged.", "blocked": "Blocked: {0}", "verifyFailed": "Merge landed, but the list's verify command failed — the task was kept out of Done.", "untrackedCollision": "Merge refused — it would overwrite an untracked file in the target working directory.", "dirtyTarget": "Merge refused — the target working directory has uncommitted changes.", "unknownStatus": "Unknown status: {0}", "mergeFailed": "Merge failed: {0}" },
     "settingsModal": { "workerOffline": "Worker offline — settings read-only.", "saveFailed": "Save failed: {0}" },
     "onlineInbox": { "workerOffline": "Worker offline — cannot load config.", "saved": "Config saved.", "saveFailed": "Save failed: {0}", "signedIn": "Signed in successfully.", "signedInNoRole": "Signed in, but this account is missing the 'user' role in Zitadel — online sync will be rejected until the role is granted in the ClaudeDo project.", "signInFailed": "Sign-in failed: {0}", "signedOut": "Signed out.", "signOutFailed": "Sign-out failed: {0}" },
     "tickets": { "connectionOk": "Connected as {0}.", "connectionMissingScopes": "Connected as {0}, but missing scopes: {1}", "tokenCleared": "Token removed.", "workerOffline": "Worker not reachable." },
@@ -870,7 +871,7 @@
     "worktreesTab": { "workerOffline": "Worker offline.", "removed": "Removed {0} worktree(s).", "blocked": "Cannot force-remove: {0} task(s) still running. Cancel them first.", "removedFrom": "Removed {0} worktree(s) from {1} task(s).", "cleanupFailed": "Cleanup failed: {0}", "resetFailed": "Reset failed: {0}" },
     "worktreesOverview": { "titleAll": "Worktrees", "titleList": "Worktrees — {0}", "listFallback": "list", "cleanupFailed": "Cleanup failed.", "cleanupFailedDetailed": "Cleanup failed: {0}", "removed": "Removed {0} worktree(s).", "discardConfirm": "Discard the worktree for \"{0}\"? Uncommitted work will be lost.", "discardFailed": "Failed to discard worktree.", "keepFailed": "Failed to keep worktree.", "cannotForceRunning": "Cannot force-remove a running task.", "forceRemoveFailed": "Force remove failed.", "forceRemoveFailedDetailed": "Force remove failed: {0}", "batchDone": "Merged {0}, {1} need resolution.", "openInExplorerFailed": "Couldn't open path: {0}" },
     "listSettings": { "untitled": "Untitled", "ticketProjectNone": "— none —", "loadFailed": "Couldn't load list settings: {0}", "ticketProjectsLoadFailed": "Couldn't load ticket projects: {0}", "confirmDeleteFolder": "Delete folder \"{0}\"? The lists inside it are kept and move back to the top level.", "confirmDeleteList": "Delete list \"{0}\" and all its tasks? This cannot be undone.", "deleteBlockedPlanning": "This list has planning sessions with child tasks. Discard those first, then delete the list.", "workingDirMissing": "This folder doesn't exist.", "workingDirNotRepo": "This folder isn't a git repository yet. Run `git init` in it first, or clear the working directory to save this as a manual list." },
-    "detailsIsland": { "verifyFailed": "Merge landed, but the list's verify command failed — the task was kept out of Done.", "untrackedCollision": "Merge refused — it would overwrite an untracked file in the target working directory.", "stopOffline": "Worker offline — can't stop the task.", "stopFailed": "Stop failed: {0}", "enqueueFailed": "Queue failed: {0}", "dequeueFailed": "Remove from queue failed: {0}", "resetAndRetryFailed": "Reset & retry failed: {0}", "toggleDoneFailed": "Couldn't update done state: {0}" },
+    "detailsIsland": { "verifyFailed": "Merge landed, but the list's verify command failed — the task was kept out of Done.", "untrackedCollision": "Merge refused — it would overwrite an untracked file in the target working directory.", "dirtyTarget": "Merge refused — the target working directory has uncommitted changes.", "stashAndMergeConfirm": "The target working directory has uncommitted changes.\nStash them, merge, and restore them afterwards?", "stopOffline": "Worker offline — can't stop the task.", "stopFailed": "Stop failed: {0}", "enqueueFailed": "Queue failed: {0}", "dequeueFailed": "Remove from queue failed: {0}", "resetAndRetryFailed": "Reset & retry failed: {0}", "toggleDoneFailed": "Couldn't update done state: {0}" },
     "mergeSection": { "openWorktreeFailed": "Couldn't open worktree: {0}" },
     "about": { "openPathFailed": "Couldn't open path: {0}" },
     "lists": { "localSuffix": "{0} / local", "smartMyDay": "My Day", "smartImportant": "Important", "smartPlanned": "Planned", "smartNotes": "Notes", "virtualQueue": "Queue", "virtualRunning": "Running", "virtualReview": "Review", "newList": "New list", "findingsNotFound": "No findings yet for this list.", "findingsOpenFailed": "Couldn't open findings folder: {0}", "openInExplorerFailed": "Couldn't open path: {0}" },