Follow-up: Performance and stability improvements post-[#96]

[ryanmcd118]

This PR is a follow-up to the recent [ #96 ] functional changes, focusing specifically on performance and stability improvements identified during post-merge review and Lighthouse audits. It reduces initial JS work, shrinks network payloads, and fixes a webpack asset naming conflict. It also restores proper navbar image rendering and maintains full test coverage.

Changes

• Added proper viewport meta tag and removed unused logo preload.
• Lazy-loaded heavy UI components (React Flow, CodeMirror) with React.Suspense while preserving test stability.
• Restored navbar logos to correct size via CSS; enabled async decoding.
• Enabled bundle splitting and fixed dev/prod filename collisions in webpack.
• Updated tests to handle async loading.

Impact

• Performance: Faster LCP/FCP by deferring non-critical scripts and splitting chunks.
• Stability: Eliminated asset name conflicts and 404s.
• UI: Clean, correctly sized navbar logos.

Verification

• npm run dev → app loads without filename conflicts; navbar logos render correctly; no 404s.
• Lazy-loaded components appear when triggered.
• npm run lint and NODE_ENV=test npm test → all tests pass.

[ryanmcd118]

👍