perf: optimize application loading and workflows

[AussieScorcher]

Summary

Improves perceived and measured frontend performance across navigation, public pages, contribution tools, the draft generator, and staff workflows. It also adds repeatable profiling/React diagnostics and documents the product design principles guiding the interface work.

Changes Made

• Adds cached lazy-route imports, intent-based route preloading, stable application shell rendering, route-aware loading skeletons, and reduced-motion-friendly reveal behavior.
• Reduces unnecessary React state and rerenders in authentication, map, contribution, division, and staff-management workflows while standardizing shared controls and loading states.
• Adds performance tracing and React diagnostic tooling, refreshes public/staff interface details and the About asset, and removes obsolete components, hooks, pages, and utilities.

Additional Information

The main performance issues were whole-page Suspense transitions, repeated route loading, mirrored UI state, controlled high-frequency map state, and legacy modules that increased maintenance and bundle surface.

User impact: navigation keeps the application shell stable, loading states better match destination content, interactive workflows do less avoidable work, and administrative screens are more consistent and accessible.

Validation:

• npm run lint
• npm run test — 63 tests passed
• npm run build
• bunx react-doctor@latest --verbose --scope changed — no issues found

The production build succeeds with advisory warnings for chunks larger than 500 kB.

Author Information

Discord Username:
VATSIM CID:

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Checklist:

• Have you followed the guidelines in our Contributing document?
• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

[greptile-apps]

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