Fix legacy TileId coordinate conversion

[josephbirkner]

Summary

• convert both legacy mapget tile-grid axes into PackedTileId's signed NDS Morton coordinate order
• cover a known legacy Germany tile in the model and MapTileKey tests
• verify legacy GeoJSONFolder manifest and filename ingestion resolve to the correct packed tile

Root cause

legacyTileIdToPacked passed the legacy X/Y grid coordinates directly to PackedTileId::fromTileXY. The legacy grid starts at the antimeridian and north pole, while PackedTileId grid coordinates are derived from signed NDS coordinates in two's-complement Morton order. The resulting tiles therefore landed in the wrong geographic region.

Validation

• cmake --build build --target test.mapget -- -j8
• focused TileId, MapTileKey, and GeoJsonSource tests
• full 105-test suite; the two Python integration tests were rerun serially because parallel local ndslive-math wheel builds share a build directory

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Package	Line Rate	Branch Rate	Health
libs.geojsonsource.include.geojsonsource	100%	50%	✔
libs.geojsonsource.src	66%	38%	➖
libs.gridsource.include.gridsource	0%	0%	❌
libs.gridsource.src	0%	0%	❌
libs.http-datasource.src	48%	26%	❌
libs.http-service.src	58%	24%	➖
libs.location.include.mapget.location	100%	100%	✔
libs.location.src	83%	40%	✔
libs.logging.include.mapget	5%	2%	❌
libs.model.include.mapget.model	51%	30%	➖
libs.model.src	73%	42%	➖
libs.service.include.mapget.service	56%	50%	➖
libs.service.src	74%	38%	➖
Summary	65% (12147 / 18562)	35% (12928 / 37286)	➖

Minimum allowed line rate is 50%