Add admin farm management page

[VidsterBroyo]

Summary

• Adds the admin Farm Management page at /admin/farms: loads approved farms, sortable/filterable horizontally scrollable table, row selection, and CSV export (selected rows or all farms when none are selected)
• Clicking a row opens a farm details modal with skeleton loading, edit/delete actions, and a two-column layout reusing the pending-request review components (FarmRequestContact, FarmRequestGallery, FarmRequestSections)
• Extracts shared admin modal shell (FarmModalShell) from FarmRequestModal and FarmDetailsModal, and promotes ConfirmDialog / ToastHost to shared components used across admin pages
• added CSV export to it too

Refactors

• Generalizes toast state to support an optional title (used for “CSV Export Complete” success toasts)
• Moves chevron icons from images/admin to images/common
• Reuses farmOptions constants in admin-farms.ts instead of duplicating string literals
• Adds explicit $lib path aliases to tsconfig.json as a fallback when .svelte-kit/tsconfig.json is unavailable locally

Farms._.Admin.-.Google.Chrome.2026-08-17.19-01-27-compressed.mp4

[github-actions]

Visit the preview URL for this PR (updated for commit 40256df):

https://mississippi-farm-to-scho-11069--pr121-feature-admin-fa-kuz6cdok.web.app

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