Publish search-indexable HTML engineering documentation

[masarray]

Purpose

Complete the next repository-hardening phase by turning every Markdown engineering guide into a dedicated, indexable HTML page on GitHub Pages.

Changes

• Add a repository-owned, dependency-free Python public-site builder.
• Generate one canonical HTML page for every docs/*.md source file.
• Generate compact documentation navigation, client-side topic filtering, breadcrumbs, source links, and responsive documentation styling.
• Add per-page description metadata, Open Graph metadata, Twitter Card metadata, and TechArticle JSON-LD.
• Generate a documentation search index and a multi-page sitemap containing the product homepage plus every documentation page.
• Build the staged public site in CI and Pages instead of copying raw Markdown into the deployment artifact.
• Add recursive validation for all HTML pages, structured data, canonical uniqueness, local links/assets, search-index targets, sitemap coverage, web-manifest icons, and robots metadata.
• Link the product landing page directly to Quick Start, SV Profile Support, COMTRADE Replay, Subscriber Verification, Safety Boundaries, and the complete documentation index.

Validation completed

• Public-site builder: success.
• Recursive validation across the landing page and all generated documentation pages: success.
• Canonical URL uniqueness, local asset/link checks, JSON-LD parsing, search-index targets, sitemap coverage, manifest icons, and robots metadata: success.
• Publisher warning-free build: success.
• Subscriber warning-free build: success.
• Unit tests and protocol-core coverage regression gate: success.
• Publisher and Subscriber dependency vulnerability reports: success.
• Full-solution warning-free CodeQL build and analysis: success.

The Windows release workflow is intentionally not triggered because this PR changes only public-site, documentation, and validation paths. No public release is created by this pull request.

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.
To continue using code reviews, you can upgrade your account or add credits to your account and enable them for code reviews in your settings.