docs: surface Nous Portal on pages where it solves a real problem the page describes (#30874)

Follow-up to #30869. Adds Portal mentions on user-facing pages that
naturally call for an LLM + tool credentials but didn't previously
acknowledge Portal as a one-stop option.

- getting-started/installation.md: tip after the 'after install' block
  pointing at 'hermes setup --portal' for users who want everything wired
  at once instead of piecewise via 'hermes model' + 'hermes tools'.
- user-guide/configuring-models.md: small tip near the top — the page is
  literally about provider/model choice and previously had zero Portal
  mention.
- user-guide/features/voice-mode.md: Prerequisites need both an LLM and
  TTS — a Portal subscription is the single setup that covers both.
- user-guide/features/batch-processing.md: highlights Portal as a
  predictable-cost option for parallel agent runs that hit many APIs.
- user-guide/features/api-server.md: backend needs models + tools; one
  Portal sub gives a fully-equipped OpenAI-compatible endpoint.
- user-guide/windows-native.md: early-beta users on Windows benefit most
  from skipping per-tool Windows-key-juggling.
- integrations/providers.md: updates the existing Tool Gateway tip and
  the Nous Portal section to mention the new commands.
- user-guide/features/fallback-providers.md: Nous row in the provider
  table now lists 'hermes setup --portal' as the fresh-install path.

Tone discipline: one Portal mention per page, concrete CLI commands
(no marketing copy), always solving a problem the page itself sets up.

website/docs/integrations/providers.md

@@ -148,7 +148,7 @@ Even when using Nous Portal, Codex, or a custom endpoint, some tools (vision, we
 :::
 
 :::tip Nous Tool Gateway
-Paid Nous Portal subscribers also get access to the **[Tool Gateway](/docs/user-guide/features/tool-gateway)** — web search, image generation, TTS, and browser automation routed through your subscription. No extra API keys needed. It's offered automatically during `hermes model` setup, or enable it later with `hermes tools`.
+Paid Nous Portal subscribers also get access to the **[Tool Gateway](/docs/user-guide/features/tool-gateway)** — web search, image generation, TTS, and browser automation routed through your subscription. No extra API keys needed. On a fresh install, `hermes setup --portal` logs you in, sets Nous as your provider, and turns the gateway on in one command. Existing users can enable it from `hermes model` or per-tool from `hermes tools`. Inspect routing at any time with `hermes portal status`.
 :::
 
 ### Two Commands for Model Management
@@ -164,7 +164,12 @@ If you're trying to switch to a provider you haven't set up yet (e.g. you only h
 
 ### Nous Portal
 
-Subscription-based access to Hermes-4 models (`Hermes-4-70B`, `Hermes-4.3-36B`, `Hermes-4-405B`) via Nous Research's portal. Run `hermes model`, pick **Nous Portal**, sign in through the browser — Hermes stores a long-lived refresh token at `~/.hermes/auth.json`.
+Subscription-based access to Hermes-4 models (`Hermes-4-70B`, `Hermes-4.3-36B`, `Hermes-4-405B`) via Nous Research's portal. Two paths:
+
+- **Fresh install:** `hermes setup --portal` — runs OAuth, sets Nous as your provider, and offers the [Tool Gateway](/docs/user-guide/features/tool-gateway) in one command.
+- **Existing install:** `hermes model`, pick **Nous Portal**, sign in through the browser.
+
+Either path stores a long-lived refresh token at `~/.hermes/auth.json`. Check status with `hermes portal status`.
 
 The refresh token is also shared across profiles via a shared token store, so logging in on one profile carries over to the others.