feat: unify signature channel reporting status

api/prisma/migrations/20260712170000_normalize_report_field_types/migration.sql

@@ -0,0 +1,9 @@
+UPDATE "DrainageField"
+SET "fieldType" = 'string'
+WHERE "fieldType" NOT IN ('string', 'image', 'file');
+
+UPDATE "ChannelReportField"
+SET "fieldType" = CASE
+  WHEN "fieldType" IN ('string', 'image', 'file') THEN "fieldType"
+  ELSE 'string'
+END;