fix(cli): harden hermes portal SystemExit handling + finish model-pick doc sweep

Self-review of #38465 surfaced three real items:

1. SystemExit escape (defense): `_login_nous` raises SystemExit(130)/(1) on
   cancel/failure. The logged-out login path inside `_model_flow_nous` catches
   it, but the expired-session re-login path (main.py) only catches Exception,
   so a Ctrl-C during re-auth could propagate past `_run_portal_one_shot` and
   kill the CLI. Add SystemExit to the portal handler so all cancel/abort cases
   end with the graceful 'Setup cancelled / retry later' message.

2. Doc sweep: the model-pick step was only added to the bare-`hermes portal`
   prose. Propagate it to the surfaces describing `hermes setup --portal`
   behavior that still omitted model selection:
   - `--portal` argparse help (main.py)
   - nous-portal.md intro + the numbered 'what it does' step list (EN + zh-Hans)
   - run-hermes-with-nous-portal.md 'default model after setup --portal' line,
     which was now contradictory (there's a picker, not a forced default) (EN + zh)

3. Test coverage: add parametrized regression test asserting the portal handler
   swallows KeyboardInterrupt / EOFError / SystemExit (returns None, no escape).

Note on 'Skip (keep current)': delegating to _model_flow_nous means picking
Skip preserves the prior provider instead of force-switching to nous — this is
intentional and matches quick setup exactly; docs now say 'sets Nous as your
provider (when you pick a model)' rather than unconditionally.

hermes_cli/setup.py

@@ -2770,7 +2770,12 @@ def _run_portal_one_shot(config: dict) -> None:
         from hermes_cli.main import _model_flow_nous
 
         _model_flow_nous(config)
-    except (KeyboardInterrupt, EOFError):
+    except (KeyboardInterrupt, EOFError, SystemExit):
+        # _login_nous raises SystemExit(130)/(1) on cancel/failure; the
+        # logged-out path inside _model_flow_nous catches it, but the
+        # expired-session re-login path only catches Exception, so a
+        # SystemExit there would otherwise escape and kill the whole CLI.
+        # Treat all of these as a graceful cancel/abort for the portal flow.
         print()
         print_info("  Setup cancelled.")
         print_info("  You can retry later with `hermes portal`.")