Load documentation by page and examples near the viewport

[Floating-Y]

Why

The shared entry loaded home-page charts and every document body on unrelated routes. Standalone Block previews also imported the listing's Code panel and highlighter. Within a document, every ComponentPreview still mounted its example and requested its raw source immediately, including previews far below the viewport and unused source for hideCode previews.

What changes

• Lazy-load Home and the document renderer; separate the metadata-only catalog, layout and component directory from document bodies.
• Generate one JSON body per section/slug, load only the selected body with import.meta.glob, clean deleted pages, and assert catalog/body consistency. Preserve loading layout, errors, fast-navigation isolation, anchors and history.
• Move BlockView into its own entry while preserving theme, image fallback and Toaster behavior.
• Normalize Windows document input and invoke the installed registry CLI through Node. Registry contents and dependencies remain unchanged.
• Activate document previews once they enter a 300px viewport margin, reusing React.lazy, import.meta.glob and the existing cache. Keep activated examples mounted so inputs, selections and expanded code survive scrolling.
• Load ordinary preview source on activation and never request raw source for hideCode previews. Preserve three-line summaries, View Code, full code, copying and installation ComponentSource loading.
• Reserve loading space while retaining custom/responsive heights. Clean up observers under StrictMode, load immediately without IntersectionObserver, and surface failures through the existing document error boundary. Guard the table-of-contents observer for the same fallback.
• Add a dependency-free browser behavior check. Keep /dev/examples on its independent full-mount path.

How it was checked

Based on dev b328113; retains upstream fragment-link and malformed-escape fixes.

Current preview implementation:

• npm run docs, npm run typecheck, npm run build and git diff --check passed. The generated registry has no committed changes.
• node --test scripts/block-metadata.test.mjs: 8 passed.
• /scripts/check-component-preview.html, served by npm run dev: 11 behavior assertions passed, covering first activation, non-intersecting callbacks, retained input/DOM/code state, hideCode source suppression, StrictMode cleanup and fallback without IntersectionObserver.
• /dev/examples: 389/389 mounted, 0 failed.
• Button, Input, Chart and Calendar checked in light/dark themes, desktop and 390px layouts: expanded code, copying, scroll-away/return, directory links, direct hash URLs and browser back/forward. Input values, Chart selection and Calendar selection remained after scrolling. Custom heights, including Input's 32rem and Calendar's 560px preview, were retained.
• Installation Manual source loading checked. Both example and raw-source requests were deliberately made to return 500: the document showed a visible error instead of loading indefinitely. Disabling IntersectionObserver still loaded the Button document immediately.
• Actual development request records: Button's first view requested only button-demo JS and raw source among its 14 previews. button-size made no own JS/raw requests at approximately 350px below the viewport; both appeared at approximately 250px. Chart's chart-demo and chart-tooltip requested JS and no raw source. Direct hash navigation loaded previews near the target. Shared dependencies may already be requested by other visible examples.

Earlier route-split validation, recorded for a264b58:

• npm ci; 76-document catalog/body consistency, repeated generation and add/delete checks.
• /dev/examples: 389/389 mounted, 0 failed in both themes.
• Headless Chrome at 1440x1000, dark/light, with both / and /solid-glass/: search, navigation, invalid URLs, delayed loading, rapid navigation, failed-body recovery, preview and image fallback.
• Production responses mapped to Vite chunk.modules: Home loaded no document bodies/Markdown; installation loaded only its body and no Recharts; the component directory loaded no bodies; login-03 loaded no bodies, Markdown, Recharts, Code panel or highlighter. Development-only example data was absent from production. The prior response-byte measurements were not repeated after the preview change.

Other browsers and physical devices were not tested. Auto-height placeholders remain estimates (Chart measured 404px before loading and about 431px afterward at a 506px viewport). Existing nativeButton and value/defaultValue development warnings remain outside this change. No speedup percentage is claimed.

Before review

• Every commit is signed off (DCO)
• npm run typecheck and npm run build pass
• /dev/examples reports 0 failed
• Affected pages checked in both themes, including open code
• No material, registry, dependency or URL changes