Parent: #142 ## Description `SubmitSightingPage.tsx` handles form state, validation, server errors, reverse geocoding and the full form layout. Refactor it into smaller, cohesive pieces where that makes the code easier to understand and maintain. ## Tasks - Extract form state or validation into focused modules if useful. - Split the form into logical sections where useful. - Reuse field markup only where it reduces meaningful duplication. - Preserve existing behavior, accessibility and tests. ## Done when The report page is easier to maintain, and its existing behavior and accessibility remain covered by tests.