perf: eliminate popover data duplication via DOM lookup (~50% per-type size reduction)

[mikaello]

Summary

Implements performance optimization 1 from #361 (comment).

Previously, named_type_details HTML was rendered twice per type at server startup:

1. Once into the hidden <section> elements
2. Again into a <script id="popover-data" type="application/json"> JSON blob

The JSON blob was then parsed at page load and used to populate Bootstrap popovers on hover.

Changes

• Remove buildPopoverData() from static_content.js — no more double-rendering
• Remove <script id="popover-data"> from top_level.njk
• Remove popover_title.njk — was only used by buildPopoverData()
• Rewrite setupPopovers() in avrodoc.js to use findSection(href) and read popover title/content directly from the existing DOM elements:
  • Title: extracted from h2.namespace + h1.type-name in the section
  • Content: .type-details innerHTML (new wrapper div in named_type.njk)
• Add <div class="type-details"> wrapper in named_type.njk to allow clean content extraction without duplicating the heading elements in the popover body

Result

• Per-type HTML cost: ~3.8 KB → ~2.6 KB (~32% reduction per type)
• At 1000 types: ~4 MB → ~2.6 MB
• At 5000 types: ~19 MB → ~13 MB
• Eliminates the popoverData JSON parse on page load
• Popovers now work for all navigable types including shared types (#/schema/<qualifiedName>), which were previously excluded from popover data

[github-actions]

Avrodoc Preview 🔍

A live preview of the generated documentation is available at:
👉 https://mikaello.github.io/avrodoc-plus/pr-preview/pr-365/

This preview is built from the schemata/ directory and updates on every push to this PR.