feat: add useGeoJSON API for rendering GeoJSON on the map

[morehawes]

Introduces a new useGeoJSON composable that abstracts MapLibre source and layer management into a simple, instance-scoped API. Motivated by a mobile rendering bug in the recordings example caused by raw MapLibre layer setup; the new API fixes that and provides a clean foundation for all future GeoJSON rendering.

useGeoJSON API (src/composables/useGeoJSON.js)

• setFeature(feature) — add or update a GeoJSON Feature by id
• removeFeature(id) — remove a feature from the map
• clearFeatures() — remove all features
• setDefaults(defaults) — set default styles per geometry type

Style is driven by navigator.* properties on the feature:

• navigator.color — fill/stroke colour (auto-assigned bright primary if absent)
• navigator.opacity, navigator.width, navigator.radius, navigator.fillOpacity

Supports Point, MultiPoint, LineString, MultiLineString, Polygon, MultiPolygon. Uses round line caps/joins for smooth mobile rendering. Features queued before map:ready are applied automatically on load. Sources and layers are cleaned up on destroy with no extra teardown code required.

Exported from @ogis/navigator public API. Works in both plugin install() (pass instanceId explicitly) and Vue component setup() (resolved via inject).

Tests (tests/unit/useGeoJSON.test.js)

Full unit test coverage: 88 tests covering setFeature, removeFeature, clearFeatures, setDefaults, auto-colour assignment, invalid input, geometry type detection, and map lifecycle (pre-ready queuing, destroy cleanup).

Recordings example updated (docs/extend/feature/recordings.js)

Replaced raw addSource/addLayer/setData calls with useGeoJSON. The active track is now rendered via setFeature() / removeFeature(), with colour toggled via navigator.color property on pause/resume. Crash recovery re-queues the restored track before mount via the same setFeature() call.

Docs

• Add docs/core/5.geojson.md — full API reference with examples
• Renumber core docs: locale 5→6, theme 6→7, testing 7→8
• Update docs/extend/5.features.md to reflect useGeoJSON patterns; remove 'Build a feature inside Navigator source' from summary table
• Add GitHub-style [!NOTE]/[!TIP] alerts to extend docs for cross-references to core, replacing plain-text pointers that blurred the audience boundary
• Update AGENTS.md, README, and copilot-instructions with current state

Other

• bump: 1.0.24 → 1.0.25
• fix: npm test now runs vitest only; E2E separated to test:e2e
• chore: remove FEEDBACK.md; add TASKS.md