Remove remaining legacy raster decommission residue

[stef-k]

Summary

• remove ownerless legacy proactive-raster API, progress, view-model, coordinate, and documentation residue
• preserve request-driven interactive OSM live caching and installed schema-v7 cleanup
• preserve downloaded Trip content, bounding boxes, navigation, synchronization, queues, authentication, and mobile API contracts
• replace source-text evidence with a runtime TripContentService progress contract

Closes #252

Product behavior

Trip metadata synchronization now reports only its real Trip-data stages and completion. It no longer exposes obsolete raster-coverage progress. Interactive OSM tiles remain request-driven and continue to use the existing provider-scoped live cache, diagnostics, eviction, and storage behavior.

The cleanup removes unused mobile boundary wrappers and no-op compatibility remnants without changing the Wayfarer backend or any retained mobile API route, verb, DTO, serialization, cursor, or authentication behavior.

Validation

• focused raster/live-cache/migration selection: passed
• runtime TripContentService progress contract: passed
• Trip content/synchronization selection: 36 passed
• complete test suite: 1,886 passed, 0 failed, 0 skipped
• Release test/Core build: passed, 0 errors
• Android Release build: passed, 0 errors; 133 retained package/XAML warnings
• forced test/Core compilation: 9 retained warnings, 0 errors
• Code Guard: REVIEW for one cohesive 85-line runtime test; LOC, nesting, and complexity passed
• git diff --check f927fa3e...HEAD: passed
• no public OSM, Wayfarer production, database, or provider contact

Migration and data safety

• no new schema or migration
• schema-v7 raster-decommission migration remains intact and idempotent
• current databases, Timeline state, pending queues, downloaded Trips, saved Segment geometry, navigation data, protected settings, and the live OSM cache are preserved

Compatibility notes

• WayfarerMobile Fix mobile group peer-visibility HTTP method compatibility #254 separately owns the pre-existing reachable peer-visibility PATCH/backend POST mismatch and is sequenced before Decommission public OSRM and add offline-capable Wayfarer routing #253
• the dormant unused user-specific SSE subscription mismatch remains unchanged and is retained for the coordinated #505 API audit
• no routing or OSRM behavior changes are included

UI evidence

No screenshot is needed: this removes obsolete unreachable behavior and terminology without adding or redesigning UI.

[github-actions]

Package	Line Rate	Branch Rate	Complexity	Health
WayfarerMobile.Core	87%	79%	1000	✔
Summary	87% (1381 / 1579)	79% (691 / 874)	1000	✔