Improve GEO metadata for existing docs pages

[AvdLee]

Summary

• Expands existing structured data for RocketSim pages with richer SoftwareApplication, WebPage, Blog/ItemList, article, and FAQ schema.
• Updates LLM discovery through generated llms.txt content, robots.txt hints, and alternate links to LLM text resources.
• Refreshes the fallback site description to reflect current Simulator, networking, accessibility, and AI-agent positioning.

Test plan

• npm run lint
• npm run format:check
• npm run typecheck
• npm run build
• npm run knip

[Copilot]

Pull request overview

This PR expands RocketSim’s SEO/LLM discovery metadata by enriching JSON-LD structured data across key pages, adding llms.txt discovery links, and updating robots/copy to better reflect current positioning.

Changes:

• Adds richer JSON-LD for static pages, feature listings, blog index/posts, and pricing FAQs (SoftwareApplication, WebPage, ItemList, FAQPage, BlogPosting).
• Improves LLM discovery via <link rel="alternate" ...> entries for llms.txt resources and updated robots.txt guidance.
• Refreshes default site meta description and expands generated llms.txt content.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
docs/src/pages/pricing.astro	Adds FAQ data into structured data for the pricing page.
docs/src/pages/index.astro	Introduces richer structured data (software + page) for the homepage.
docs/src/pages/features/[featurePageSlug].astro	Adds canonical URL reuse plus ItemList-style structured data for feature category pages.
docs/src/pages/blog/index.astro	Adds Blog landing page structured data including an ItemList of posts.
docs/src/pages/blog/[slug].astro	Adds word count and image caption into article SEO/JSON-LD.
docs/src/layouts/components/StructuredData.astro	Major expansion of JSON-LD graph generation (SoftwareApplication/WebPage/ItemList/FAQPage improvements).
docs/src/layouts/components/SEO.astro	Adds alternate links for llms.txt and llms-full.txt.
docs/src/integrations/llms-txt-post-process.ts	Updates generated llms.txt content with richer positioning + canonical doc links.
docs/src/config/config.json	Updates fallback meta description copy.
docs/src/components/starlight/Head.astro	Adds llms.txt alternate links for Starlight docs pages.
docs/public/robots.txt	Adds explicit allow rules and LLM-friendly documentation references.

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