feat(schemas): add SYSTEM kind discriminator for non-spatial state

[IanMayo]

Summary

• Add SYSTEM kind to FeatureKindEnum for storing non-spatial application state as GeoJSON Features with geometry: null
• Implement three state variants: temporal viewport, spatial viewport, and selection state
• Generate validated Pydantic, TypeScript, and JSON Schema outputs from LinkML master
• Add comprehensive fixture-based validation tests (valid + invalid cases)

Changes

Schema Changes

• Add SYSTEM to FeatureKindEnum in common.yaml
• Add SystemStateTypeEnum (temporal, spatial, selection) in common.yaml
• Add SystemStateProperties class with variant-specific fields in geojson.yaml
• Add SystemState feature class with state.* ID pattern validation

Test Fixtures

• system-state-temporal-01.json - Time viewport state
• system-state-spatial-01.json - Map viewport state (bbox, zoom, center)
• system-state-selection-01.json - Selected feature IDs
• system-state-invalid-geometry.json - Tests non-null geometry rejection
• system-state-invalid-id.json - Tests ID pattern validation

Documentation

• Updated README.md with SYSTEM feature usage examples

Evidence

Test Results

Metric	Value
Total Tests	124
Golden Fixture Tests	53
SYSTEM Fixtures	5 (3 valid, 2 invalid)
Warnings	6 (pre-existing LinkML limitation)

Key scenarios verified:

• Valid temporal, spatial, and selection fixtures pass Pydantic validation
• Invalid fixtures correctly rejected (non-null geometry, wrong ID pattern)
• All existing tests pass (no regressions)

Usage Example

from debrief_schemas import SystemState, SystemStateProperties

temporal_state = SystemState(
    type="Feature",
    id="state.temporal",
    geometry=None,
    properties=SystemStateProperties(
        kind="SYSTEM",
        state_type="temporal",
        start_time="2024-01-15T09:00:00Z",
        end_time="2024-01-15T17:30:00Z"
    )
)

Sample Temporal Viewport JSON

{
  "type": "Feature",
  "id": "state.temporal",
  "geometry": null,
  "properties": {
    "kind": "SYSTEM",
    "state_type": "temporal",
    "start_time": "2024-01-15T09:00:00Z",
    "end_time": "2024-01-15T17:30:00Z"
  }
}

Sample Spatial Viewport JSON

{
  "type": "Feature",
  "id": "state.spatial",
  "geometry": null,
  "properties": {
    "kind": "SYSTEM",
    "state_type": "spatial",
    "bbox": [-5.5, 49.5, 1.5, 55.0],
    "zoom": 8.5,
    "center": [-2.0, 52.25]
  }
}

Test Plan

• All 124 Python tests pass
• TypeScript compilation succeeds
• JSON Schema validation tests pass
• Valid SYSTEM fixtures validate correctly
• Invalid SYSTEM fixtures are rejected with appropriate errors
• No regressions in existing fixture tests

Related

• Spec: specs/022-system-kind-discriminator/spec.md
• Tasks: specs/022-system-kind-discriminator/tasks.md
• Evidence: specs/022-system-kind-discriminator/evidence/