Performance & bundle size optimisations

## Description

- I imagine performance is probably bottle of the pile of priorities, over actual functionality, and I would agree if that's the case!
- But over time I think we can probably optimise the performance of stac-map.
- [Lighthouse report attached](https://github.com/user-attachments/files/27768224/imagery.hotosm.org-20260514T171547.html)
- FCP was 7.2s on a pretty good internet connection, using [vanilla stac-map](https://developmentseed.org/stac-map/) (7.9s on our [modified site](https://imagery.hotosm.org))
- In the network tab I see 83.9 MB of resources loaded by the page, presumably after they have been decompressed, but it's still a fair bit of content to load!

duckdb and stac-wasm packages are pretty large network payloads:
- 9,808.5 KiB stac-wasm
- 6,607.1 KiB duckdb-eh.wasm
- 5,851.2 KiB spatial.duckdb_extension.wasm

They are used for geoarrow and geoparquet functionality by the looks of it?
Could we possibly make loading these libs optional / opt-out?

I'm sure there are other things to look at too, but those a just some initial points 😄

## Use case

- Those on limited internet connections would probably appreciate a slightly leaner page load.

## Additional context

- I guess if the internet connection is bad enough to struggle loading this, then loading the STAC and asset images etc would be a problem too.