fix(workspace-state): stop resync loop on non-git folders and allow retry for degraded watcher

Gate git refresh on .git presence so file churn in non-git workspaces no longer produces endless resync_hint events, and silently log tree/git refresh errors during watch flushing instead of flagging requires_resync, which turned transient failures into self-reinforcing loops.

Degrade gracefully when the filesystem watcher fails to attach (e.g. permission denied, inotify quota): keep the initial snapshot, surface a degraded flag, and expose a store-level restart that the banner uses to retry attachment after the root cause is fixed.

Propagate is_git_repo through the snapshot so the git log and changes tabs render a dedicated "Not a Git repository" empty state instead of raw git stderr with a useless retry button.

Stop polling get_git_branch from the title bar once it returns null and re-arm on visibility change.

Add translations for the new banner, empty-state, and retry keys across all ten locales.

src/components/layout/aux-panel-file-tree-tab.tsx

@@ -19,6 +19,7 @@ import { useTabContext } from "@/contexts/tab-context"
 import { useTerminalContext } from "@/contexts/terminal-context"
 import { useWorkspaceContext } from "@/contexts/workspace-context"
 import { useWorkspaceStateStore } from "@/hooks/use-workspace-state-store"
+import { WorkspaceDegradedBanner } from "@/components/layout/workspace-degraded-banner"
 import {
   createFileTreeEntry,
   deleteFileTreeEntry,
@@ -2001,6 +2002,9 @@ export function FileTreeTab() {
 
   return (
     <div className="flex flex-col h-full">
+      {workspaceState.degraded && (
+        <WorkspaceDegradedBanner onRetry={workspaceState.restart} />
+      )}
       <ContextMenu>
         <ContextMenuTrigger asChild>
           <ScrollArea className="flex-1 min-h-0 pb-1" x="scroll">