feat(image_gen): upgrade Recraft V3 → V4 Pro, Nano Banana → Pro (#11406)

* feat(image_gen): upgrade Recraft V3 → V4 Pro, Nano Banana → Pro

Upstream asked for these two upgrades ASAP — the old entries show
stale models when newer, higher-quality versions are available on FAL.

Recraft V3 → Recraft V4 Pro
  ID:    fal-ai/recraft-v3 → fal-ai/recraft/v4/pro/text-to-image
  Price: $0.04/image → $0.25/image (6x — V4 Pro is premium tier)
  Schema: V4 dropped the required `style` enum entirely; defaults
          handle taste now. Added `colors` and `background_color`
          to supports for brand-palette control. `seed` is not
          supported by V4 per the API docs.

Nano Banana → Nano Banana Pro
  ID:    fal-ai/nano-banana → fal-ai/nano-banana-pro
  Price: $0.08/image → $0.15/image (1K); $0.30 at 4K
  Schema: Aspect ratio family unchanged. Added `resolution`
          (1K/2K/4K, default 1K for billing predictability),
          `enable_web_search` (real-time info grounding, +$0.015),
          and `limit_generations` (force exactly 1 image).
  Architecture: Gemini 2.5 Flash → Gemini 3 Pro Image. Quality
                and reasoning depth improved; slower (~6s → ~8s).

Migration: users who had the old IDs in `image_gen.model` will
fall through the existing 'unknown model → default' warning path
in `_resolve_fal_model()` and get the Klein 9B default on the next
run. Re-run `hermes tools` → Image Generation to pick the new
version. No silent cost-upgrade aliasing — the 2-6x price jump
on these tiers warrants explicit user re-selection.

Portal note: both new model IDs need to be allowlisted on the
Nous fal-queue-gateway alongside the previous 7 additions, or
users on Nous Subscription will see the 'managed gateway rejected
model' error we added previously (which is clear and
self-remediating, just noisy).

* docs: wrap '<1s' in backticks to unblock MDX compilation

Docusaurus's MDX parser treats unquoted '<' as the start of JSX, and
'<1s' fails because '1' isn't a valid tag-name start character. This
was broken on main since PR #11265 (never noticed because
docs-site-checks was failing on OTHER issues at the time and we
admin-merged through it).

Wrapping in backticks also gives the cell monospace styling which
reads more cleanly alongside the inline-code model ID in the same row.

The other '<1s' occurrence (line 52) is inside a fenced code block
and is already safe — code fences bypass MDX parsing.

website/docs/user-guide/features/overview.md

@@ -30,7 +30,7 @@ Hermes Agent includes a rich set of capabilities that extend far beyond basic ch
 - **[Voice Mode](voice-mode.md)** — Full voice interaction across CLI and messaging platforms. Talk to the agent using your microphone, hear spoken replies, and have live voice conversations in Discord voice channels.
 - **[Browser Automation](browser.md)** — Full browser automation with multiple backends: Browserbase cloud, Browser Use cloud, local Chrome via CDP, or local Chromium. Navigate websites, fill forms, and extract information.
 - **[Vision & Image Paste](vision.md)** — Multimodal vision support. Paste images from your clipboard into the CLI and ask the agent to analyze, describe, or work with them using any vision-capable model.
-- **[Image Generation](image-generation.md)** — Generate images from text prompts using FAL.ai. Eight models supported (FLUX 2 Klein/Pro, GPT-Image 1.5, Nano Banana, Ideogram V3, Recraft V3, Qwen, Z-Image Turbo); pick one via `hermes tools`.
+- **[Image Generation](image-generation.md)** — Generate images from text prompts using FAL.ai. Eight models supported (FLUX 2 Klein/Pro, GPT-Image 1.5, Nano Banana Pro, Ideogram V3, Recraft V4 Pro, Qwen, Z-Image Turbo); pick one via `hermes tools`.
 - **[Voice & TTS](tts.md)** — Text-to-speech output and voice message transcription across all messaging platforms, with five provider options: Edge TTS (free), ElevenLabs, OpenAI TTS, MiniMax, and NeuTTS.
 
 ## Integrations