Improve startup performance and learning navigation

[Inmerson]

Goal

• split the large single-page bundle into lazy-loaded learning screens
• add searchable topic navigation from the dashboard
• add a persistent “continue learning” destination
• improve mobile navigation accessibility and reduced-motion behavior

What changed

• added a tested catalog of learning destinations across all modules
• added dashboard topic search with / keyboard shortcut and direct navigation
• added a persistent Continue Learning card
• lazy-loaded learning views with a meaningful loading state
• respected prefers-reduced-motion and disabled dashboard tilt when requested
• added accessible names and combobox/listbox semantics

Verification

• learning catalog tests failed before implementation because the catalog module did not exist
• npm run typecheck
• npm test — 9 tests passed across 3 files
• npm run build
• initial JavaScript entry reduced from about 2.99 MB to 382.51 kB; heavy math and 3D code is loaded on demand
• GitHub Pages publishing succeeded after merge

Deployment

https://inmerson.github.io/Math-Biotech-Project/site/

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