Summary

Title: Optimize build: patch Starlight sidebar cloning (-14%)

Starlight deep-clones the full sidebar tree for every page (7,303x). Our Page.astro override replaces props.sidebar entirely, making this pure waste. Patching it out saves ~50s per build.

Changes:

• patches/@astrojs+starlight+0.37.6.patch — skip structuredClone + setIntermediateSidebarCurrentEntry in getSidebarFromIntermediateSidebar
• src/util/sidebar.ts — hoist flattenSidebar() out of O(n^2) loop
• src/util/components.ts — scan-once caching for MDX file parsing
• src/util/glossary.ts — collection caching with Map lookup, preserves original behavior

Benchmarks (cold builds):

For a detailed walkthrough and breakdown, read: investigation summary

Screenshots (optional)

Documentation checklist

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