[AZ-240] [AZ-241] [AZ-242] Add native retrieval remediation

Implement the product remediation paths required before greenfield
code testability revision: native VIO backend selection, local
VPR descriptor index retrieval, and computed anchor matching gates.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/unit/test_satellite_service_vpr.py

@@ -1,3 +1,6 @@
+import json
+from pathlib import Path
+
 from satellite_service import (
     LocalVprIndexPackage,
     LocalVprRetriever,
@@ -33,6 +36,46 @@ def test_valid_local_index_load_reports_ready_status() -> None:
     assert readiness.ready is True
     assert readiness.engine == "cpu_faiss"
     assert readiness.loaded_records == 1
+    assert readiness.package_id == "index-1"
+    assert readiness.descriptor_model == "dinov2_vlad"
+
+
+def test_local_descriptor_index_package_loads_from_cache_file(tmp_path: Path) -> None:
+    # Arrange
+    package_path = tmp_path / "vpr-index.json"
+    package_path.write_text(
+        json.dumps(
+            {
+                "package_id": "index-file-1",
+                "engine": "cpu_faiss",
+                "descriptor_model": "dinov2_vlad",
+                "records": [
+                    {
+                        "chunk_id": "chunk-file",
+                        "tile_id": "tile-file",
+                        "descriptor": [1.0, 0.0],
+                        "footprint": {
+                            "min_lat": 49.0,
+                            "max_lat": 49.1,
+                            "min_lon": 36.0,
+                            "max_lon": 36.1,
+                        },
+                        "freshness_status": "fresh",
+                    }
+                ],
+            }
+        ),
+        encoding="utf-8",
+    )
+    retriever = LocalVprRetriever()
+
+    # Act
+    readiness = retriever.load_index_from_path(package_path)
+
+    # Assert
+    assert readiness.ready is True
+    assert readiness.package_id == "index-file-1"
+    assert readiness.loaded_records == 1
 
 
 def test_loaded_index_returns_bounded_candidates_with_freshness() -> None:
@@ -65,12 +108,35 @@ def test_loaded_index_returns_bounded_candidates_with_freshness() -> None:
 
     # Assert
     assert result.degraded is False
+    assert result.retrieval_path == "local_descriptor_index"
+    assert result.latency_ms is not None
     assert len(result.candidates) == 1
     assert result.candidates[0].chunk_id == "chunk-best"
     assert result.candidates[0].tile_id == "tile-best"
     assert result.candidates[0].freshness_status == "fresh"
 
 
+def test_loaded_index_requires_query_descriptor() -> None:
+    # Arrange
+    retriever = LocalVprRetriever()
+    retriever.load_index(LocalVprIndexPackage(package_id="index-1", records=(_record(),)))
+    request = RelocalizationRequest(
+        frame_id="frame-1",
+        image_ref="replay/frame-1.jpg",
+        trigger_reason="covariance_growth",
+        top_k=1,
+    )
+
+    # Act
+    result = retriever.retrieve(request)
+
+    # Assert
+    assert result.ready is True
+    assert result.degraded is True
+    assert result.error is not None
+    assert result.error.cause == "query_descriptor_missing"
+
+
 def test_missing_index_degrades_with_explicit_no_candidate_result() -> None:
     # Arrange
     retriever = LocalVprRetriever()
@@ -92,6 +158,34 @@ def test_missing_index_degrades_with_explicit_no_candidate_result() -> None:
     assert result.error.cause == "index_not_loaded"
 
 
+def test_invalid_index_package_degrades_with_explicit_error(tmp_path: Path) -> None:
+    # Arrange
+    package_path = tmp_path / "invalid-index.json"
+    package_path.write_text("{not-json", encoding="utf-8")
+    retriever = LocalVprRetriever()
+
+    # Act
+    readiness = retriever.load_index_from_path(package_path)
+    result = retriever.retrieve(
+        RelocalizationRequest(
+            frame_id="frame-1",
+            image_ref="replay/frame-1.jpg",
+            trigger_reason="cold_start",
+            top_k=3,
+            query_descriptor=(1.0, 0.0),
+        )
+    )
+
+    # Assert
+    assert readiness.ready is False
+    assert readiness.error is not None
+    assert readiness.error.cause == "index_package_invalid"
+    assert result.ready is False
+    assert result.degraded is True
+    assert result.error is not None
+    assert result.error.cause == "index_package_invalid"
+
+
 def test_descriptor_fidelity_gate_rejects_large_optimized_delta() -> None:
     # Arrange
     retriever = LocalVprRetriever()