What type of PR is this? (check all applicable)

• 🍕 Feature
• 🐛 Bug Fix
• 📝 Documentation
• 🧑‍💻 Refactor
• ✅ Test
• 🤖 Build or CI
• ❓ Other (please specify)

Related Issue

Continuation from #1922
Fixes #1552

Describe this PR

• Added a migration to upload all basemaps on the filesystem to the S3 bucket + replace url field in the db.
  • The migration is idempotent / skips files already done, or that don't exist.
  • It also cleans up FAILED basemap download entries + their associated BackgroundTask entries.
• Now we access the url directly from the S3 bucket in the frontend, instead of calling the backend API (commented out the download endpoint until we need it for private bucket download / pre-signed).
• The mapper frontend can load a pmtiles file from a URL, or download to OPFS and use offline.
• If there is an OPFS pmtiles file already present when loading the mapper frontend, it is added to the basemap selection automatically (OPFS files persist across restarts etc).
  • Also renamed {projectId}/all.pmtiles to {projectId}/basemap.pmtiles in the OPFS storage.

Screenshots

Alternative Approaches Considered

• The long term plan is to replace the basemap functionality in FMTM and outsource to a microservice hotosm/basemap-api.
• This solution will do for now, until we migrate.

Review Guide

• The migration script must be run manually on the server after deploy!

docker compose exec api bash
cd app
python upload-basemaps-s3.py                                           

Checklist before requesting a review

• 📖 Read the FMTM Contributing Guide: https://github.com/hotosm/fmtm/blob/main/CONTRIBUTING.md
• 📖 Read the HOT Code of Conduct: https://docs.hotosm.org/code-of-conduct
• 👷‍♀️ Create small PRs. In most cases, this will be possible.
• ✅ Provide tests for your changes.
• 📝 Use descriptive commit messages.
• 📗 Update any related documentation and include any relevant screenshots.

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