CUB-235: add tests for GET /api/v1/cameras/:id endpoint

- TestGetCameraDetail_NotFound: returns 404 for missing camera
- TestGetCameraDetail_Success: returns camera + last_status + history
- TestGetCameraDetail_EmptyHistory: camera with no status logs
- TestGetCameraDetail_HistoryLimitedTo100: history capped at 100 entries
- TestGetCameraDetail_MissingID: returns 400 for empty ID param
- TestGetCameraDetail_LastStatusPresent: verifies last_status field
- db_test.go: migration smoke test (documents splitSQL comment bug)

internal/db/db_test.go

@@ -0,0 +1,49 @@
+package db
+
+import (
+	"os"
+	"strings"
+	"testing"
+)
+
+func TestOpenMigration(t *testing.T) {
+	f, err := os.CreateTemp("", "remoterig-db-test-*.db")
+	if err != nil {
+		t.Fatalf("create temp: %v", err)
+	}
+	path := f.Name()
+	f.Close()
+	defer os.Remove(path)
+
+	database, err := Open(path)
+	if err != nil {
+		t.Fatalf("Open failed: %v", err)
+	}
+	defer database.Close()
+
+	var count int
+	err = database.QueryRow("SELECT COUNT(*) FROM cameras").Scan(&count)
+	if err != nil {
+		t.Fatalf("query cameras: %v", err)
+	}
+	t.Logf("cameras table exists, count=%d", count)
+}
+
+func TestSplitSQLComments(t *testing.T) {
+	sql := migration001
+	stmts := splitSQL(sql)
+	for i, s := range stmts {
+		s = strings.TrimSpace(s)
+		if s == "" {
+			continue
+		}
+		t.Logf("Statement %d: %s", i, s[:min(len(s), 80)])
+	}
+}
+
+func min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}