Dedupe SAT test centre entries pointing to the same physical location

[AnayDhawan]

Problem

Some locations show multiple SAT centre entries in the map/data even though only one physical centre actually exists there. Looks like a data dedup issue in sat_centre.json (or upstream source), not a real multi-centre location.

Scope

• Audit data/places/sat_centre.json for duplicate entries by location/address
• Fix dedup logic in ingestion/build step if duplicates come from source data
• Verify against a few known single-centre locations

Owner

@yakew7