ingest: add status history support and drop status_at_collection

internal/api/import-example-full.json

@@ -278,8 +278,20 @@
         "firmware": "SN02",
         "interface": "SATA",
         "present": true,
-        "status": "Critical",
-        "error_description": "Error Code on GPU 0 [18:00.0] (S/N 1653925025827) = 020000190097 (unexpected device interrupts)"
+        "status": "OK",
+        "status_changed_at": "2026-02-10T15:22:00Z",
+        "status_history": [
+          {
+            "status": "Critical",
+            "changed_at": "2026-02-10T15:10:00Z",
+            "details": "I/O timeout on NVMe queue 3"
+          },
+          {
+            "status": "OK",
+            "changed_at": "2026-02-10T15:22:00Z",
+            "details": "Recovered after controller reset"
+          }
+        ]
       }
     ],
     "pcie_devices": [

internal/api/ingest_hardware_test.go

@@ -287,3 +287,88 @@ func TestIngestHardwareCreatesMachineInStock(t *testing.T) {
 		t.Fatalf("expected stock machine with null project, got project=%v", projectID.String)
 	}
 }
+
+func TestIngestHardwareStoresStatusHistoryInObservationDetails(t *testing.T) {
+	dsn := os.Getenv("DATABASE_DSN")
+	if dsn == "" {
+		t.Skip("DATABASE_DSN not set")
+	}
+
+	db, err := repository.Open(dsn)
+	if err != nil {
+		t.Fatalf("open db: %v", err)
+	}
+	defer db.Close()
+
+	if err := applyMigrations(db); err != nil {
+		t.Fatalf("apply migrations: %v", err)
+	}
+	if err := cleanupRegistry(db); err != nil {
+		t.Fatalf("cleanup: %v", err)
+	}
+
+	mux := http.NewServeMux()
+	RegisterIngestRoutes(mux, IngestDependencies{Service: ingest.NewService(db)})
+	server := httptest.NewServer(mux)
+	defer server.Close()
+
+	payload := map[string]any{
+		"target_host":  "history-server",
+		"collected_at": "2026-02-10T15:30:00Z",
+		"hardware": map[string]any{
+			"board": map[string]any{"serial_number": "HISTORY-001"},
+			"storage": []map[string]any{
+				{
+					"slot":              "Disk.Bay.0",
+					"serial_number":     "HISTORY-DISK-001",
+					"present":           true,
+					"status":            "OK",
+					"status_changed_at": "2026-02-10T15:22:00Z",
+					"status_history": []map[string]any{
+						{
+							"status":     "Critical",
+							"changed_at": "2026-02-10T15:10:00Z",
+						},
+						{
+							"status":     "OK",
+							"changed_at": "2026-02-10T15:22:00Z",
+							"details":    "Recovered after controller reset",
+						},
+					},
+				},
+			},
+		},
+	}
+	body, err := json.Marshal(payload)
+	if err != nil {
+		t.Fatalf("marshal payload: %v", err)
+	}
+
+	resp, err := http.Post(server.URL+"/ingest/hardware", "application/json", bytes.NewReader(body))
+	if err != nil {
+		t.Fatalf("post: %v", err)
+	}
+	resp.Body.Close()
+	if resp.StatusCode != http.StatusCreated {
+		t.Fatalf("expected 201, got %d", resp.StatusCode)
+	}
+
+	var historyStatus, statusChangedAt string
+	row := db.QueryRow(`
+		SELECT
+			JSON_UNQUOTE(JSON_EXTRACT(details, '$.status_history[0].status')),
+			JSON_UNQUOTE(JSON_EXTRACT(details, '$.status_changed_at'))
+		FROM observations
+		ORDER BY observed_at DESC, id DESC
+		LIMIT 1
+	`)
+	if err := row.Scan(&historyStatus, &statusChangedAt); err != nil {
+		t.Fatalf("details query: %v", err)
+	}
+	if historyStatus != "CRITICAL" {
+		t.Fatalf("expected first status_history status CRITICAL, got %q", historyStatus)
+	}
+	if statusChangedAt != "2026-02-10T15:22:00Z" {
+		t.Fatalf("expected status_changed_at=2026-02-10T15:22:00Z, got %q", statusChangedAt)
+	}
+}