Parse Segment geometry consistently for maps and navigation

[stef-k]

Summary

• add one validated Segment geometry parser for GeoJSON LineStrings and encoded polylines
• use the shared coordinate sequence in map rendering and navigation graph construction
• reject malformed, unsupported, out-of-range, and insufficient geometry deterministically
• retain navigation edges without corrupt detailed geometry when parsing fails
• preserve existing OSRM encoded-polyline handling

Closes #237

Validation

• parser tests: 21 passed, 0 failed, 0 skipped
• map/navigation tests: 27 passed, 0 failed, 0 skipped
• decoder/OSRM boundary tests: 13 passed, 0 failed, 0 skipped
• ordinary non-Android suite: 1,853 passed, 0 failed, 0 skipped
• Release tests/Core build: succeeded
• Android Release build: succeeded
• git diff --check: passed
• iOS and mounted-device validation not run

Data and migrations

No API, persistence, schema, migration, or synchronization changes.

[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
WayfarerMobile.Core	85%	80%	720	✔
Summary	85% (978 / 1149)	80% (486 / 606)	720	✔