fix(ui): report and gate ListSettingsModal load failures instead of swallowing them

BeginLoad's fire-and-forget LoadAsync now catches instead of leaving an
unobserved task exception, reports it via the new ErrorReported event
(wired into FlashFooterError like the other modal VMs), and keeps Save
locked so the failure can't clobber list_config with blank fields.
LoadTicketProjectsAsync's empty catch now reports too; behavior for the
dropdown itself is unchanged.

src/ClaudeDo.Localization/locales/en.json

@@ -772,7 +772,7 @@
     "sessionSkillsTab": { "installed": "Installed: {0}", "installFailed": "Install failed: {0}", "updated": "Updated.", "updateFailed": "Update failed: {0}", "removed": "Removed.", "removeFailed": "Remove failed: {0}" },
     "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 —" },
+    "listSettings": { "untitled": "Untitled", "ticketProjectNone": "— none —", "loadFailed": "Couldn't load list settings: {0}", "ticketProjectsLoadFailed": "Couldn't load ticket projects: {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.", "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}" },