fix(cctv): stop the Dutch cameras landing on the map twice

[meijbaard]

netherlands.ts is reached two ways: as its own key in RAW_REGION_FETCHERS, and through fetchEuropeCameras, which calls fetchNetherlandsCameras() directly. GET concatenates whatever the regions return without deduplicating, so every Rijkswaterstaat camera is pushed twice — two pins on one spot, and sources reporting 52 cameras where there are 26.

Measured

	before	after
?region=netherlands,europe → Rijkswaterstaat	52	26
...ids appearing twice	26	0
?region=all → cameras / unique ids	—	35,004 / 35,004
viewport at Harlingen → Rijkswaterstaat	26	26
viewport at Vienna → Rijkswaterstaat	none	none

Three parts, and the second is the one that is easy to miss

The call comes out of fetchEuropeCameras. The country has its own region key; fetching it inside Europe as well was the duplication.

netherlands gains a branch in getRegionsForBounds, explicit the way Utah and Oregon already are. It was never in there — the broad europe box was carrying the Dutch feed for viewport queries. Removing the call alone would have left a viewport over the Netherlands answering with no Dutch cameras at all, trading a visible bug for a silent one. The box is the one netherlands.ts already filters the feed on.

GET deduplicates on id. Regions overlap by design — a bounding box can name both europe and a country inside it — so this is a property of the merge rather than of any one source, and it keeps the next source that gets registered twice from doing the same thing. Cameras without an id are passed through untouched; several of the inline fetchers are typed any[].

Verifying

npm test        # 548 passed
npx tsc --noEmit
curl 'localhost:3000/api/cctv?region=netherlands,europe' | jq '.sources.Rijkswaterstaat'
curl 'localhost:3000/api/cctv?region=all' | jq '[.total, ([.cameras[].id] | unique | length)]'

npm run lint runs out of heap on this repo on master too, so it is not usable as a gate here. eslint src/app/api/cctv/route.ts reports the same 29 pre-existing findings before and after.

🤖 Generated with Claude Code

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