Clarify reverse-geocoding precision in map views

[stef-k]

Summary

• retain meaningful detected-place names in Location and Trip views
• hide raw provider feature classifications for specific results
• show plain-language approximation guidance for postcode, city, local-area, and regional results
• preserve stored metadata and API/import/export contracts

Closes #551

Validation

• client tests: 111 passed
• frontend typecheck and production build
• dotnet build --no-restore
• repository search found no remaining user-facing Feature type label
• git diff --check

LOC

One-time #551 exceptions were explicitly approved for the narrowly edited legacy files Manager Groups Map, User Groups Map, and Trip Viewer. No broader exception applies.