feat(web): og:image, /pricing + FAQ schema, llms-full.txt, GitHub nav

More AEO audit fixes (the content-independent quick wins):

- Generated 1200x630 OpenGraph/Twitter card (app/opengraph-image.tsx);
  drop the SVG fallback and use summary_large_image.
- /pricing page with question-style headings and FAQPage JSON-LD; clarifies
  the spec/tooling is free and implementation is $250/week.
- /llms-full.txt — full markdown of the curated docs concatenated for
  large-context RAG ingestion.
- GitHub link added to both navs (SPA rail + SiteShell) and Pricing nav item;
  /pricing added to the sitemap.

Verified in a running build: og image renders as PNG and is referenced in
head; /pricing serves FAQ + schema; /llms-full.txt concatenates docs.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/logicsrc-web/src/lib/page-markup.ts

@@ -128,8 +128,10 @@ export function renderPageMarkup(): string {
         <a href="/docs">Docs</a>
         <a href="/blog">Blog</a>
         <a href="/openspec">OpenSpec</a>
+        <a href="/pricing">Pricing</a>
         <a href="/hire-us">Hire Us</a>
         <a href="/about">About</a>
+        <a href="https://github.com/profullstack/logicsrc" target="_blank" rel="noreferrer">GitHub ↗</a>
         <a href="/terms">Terms</a>
         <a href="/privacy">Privacy</a>
         <a href="#reference">Reference</a>