feat(desktop): run tool backend post-setup installs from the GUI (#40559)

Complete the desktop app's tool-backend configuration so it fully
mirrors `hermes tools`. The toolset config panel already did
enable/disable, provider selection, and API-key save/reveal/clear — the
one remaining gap was post-setup install hooks, which previously just
told the user to run the CLI.

Now a provider that declares a post_setup hook (browser Chromium,
Camofox, cua-driver, KittenTTS/Piper, ddgs, Spotify, Langfuse, xAI)
renders a 'Run setup' button that spawns the install via the
`POST /api/tools/toolsets/{name}/post-setup` endpoint and tails the
log inline, feeding the desktop activity rail — mirroring
command-center's runSystemAction poll loop. On completion the panel
refreshes so a now-installed backend reports itself ready.

- hermes.ts: runToolsetPostSetup(name, key) -> profile-scoped POST.
- toolset-config-panel.tsx: PostSetupRunner sub-component (Run setup
  button + inline live log + activity-rail upsert + unmount guard),
  replacing the CLI-only placeholder.
- i18n: replace the orphaned `toolsets.postSetup` (CLI redirect) string
  with proper post-setup UI keys (hint / run / running / starting /
  complete / error / failed) across en, ja, zh, zh-hant + types.
- test: post-setup run+poll+log-tail coverage; mock additions for
  runToolsetPostSetup/getActionStatus/activity store.

Works against local AND remote backends: all calls route through the
desktop's single `hermes:api` IPC handler to connection.baseUrl, so a
connected remote configures the remote host's tools (keys -> remote
.env, install runs on the remote). Relies on the post-setup endpoint +
'hermes tools post-setup' CLI shipped in #40418.

Verification: tsc -b clean (all 5 locales), eslint clean (the lone
exhaustive-deps warning is pre-existing on origin/main), vitest 4/5
(new post-setup test passes; the failing 'saves an API key' test fails
identically on origin/main — pre-existing EnvVarActionsMenu drift).

apps/desktop/src/hermes.ts

@@ -443,6 +443,15 @@ export function selectToolsetProvider(
   })
 }
 
+export function runToolsetPostSetup(name: string, key: string): Promise<ActionResponse & { key: string }> {
+  return window.hermesDesktop.api<ActionResponse & { key: string }>({
+    ...profileScoped(),
+    path: `/api/tools/toolsets/${encodeURIComponent(name)}/post-setup`,
+    method: 'POST',
+    body: { key }
+  })
+}
+
 export function getMessagingPlatforms(): Promise<MessagingPlatformsResponse> {
   return window.hermesDesktop.api<MessagingPlatformsResponse>({
     path: '/api/messaging/platforms'