fix(tui): scope TUI launch install and fix stale hints/test

- Add --workspace ui-tui to the TUI launch npm install, the one call
  site missed by the prior commit. Without scoping it ran from
  PROJECT_ROOT and still resolved apps/desktop via the apps/* glob.

- Update the two manual-recovery hints in _build_web_ui (npm install
  failure and build failure paths) to use the scoped form
  `npm install --workspace web && npm run build -w web` so users
  following the hint don't accidentally trigger a desktop rebuild.

- Update the stale test assertion in test_cmd_update.py to expect
  --workspace web in the _build_web_ui npm ci call, which was
  previously unreachable through the if-guard and left the workspace-
  scoping change from the prior commit unverified.

tests/hermes_cli/test_cmd_update.py

@@ -272,7 +272,7 @@ class TestCmdUpdateBranchFallback:
             # The web/ install runs from the workspace root when the root
             # lockfile exists (npm workspaces hoist node_modules upward).
             assert npm_calls[2:] == [
-                (["/usr/bin/npm", "ci", "--silent"], PROJECT_ROOT),
+                (["/usr/bin/npm", "ci", "--silent", "--workspace", "web"], PROJECT_ROOT),
             ]
 
         # The web UI build itself went through the streaming helper.