FEAT-8d: add wipe-import-data.sql utility

Utility script to clean up import data from the database after testing
/import/dry-run. Useful for re-running the import process during development
and QA. Deletes all animals and litters created by the import (identified
by ImportSource='docx-export' and ImportSource='derived-litter'), resets
sequences, and leaves the database ready for fresh import execution.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tools/wipe-import-data.sql

@@ -0,0 +1,32 @@
+-- WIPE-IMPORT-DATA: truncate only import-derived tables, preserve seeded data.
+--
+-- Scope (god decision 2026-06-07):
+--   WIPE:   GerbilPhotos, WeightRecords, HealthRecords, Gerbils, Litters
+--   KEEP:   ColorVarieties (migration-seeded, import matches against these)
+--           BreederSettings, Sites, Pages (CMS), Contacts, Enclosures,
+--           SaleContracts, Requests, MailSettings
+--
+-- Run ONLY after pg_dump backup. FK order: dependents first.
+-- Usage (with Aspire Postgres running):
+--   docker exec -i <postgres-container> psql -U postgres gerbilmanager < tools/wipe-import-data.sql
+--   OR connect via psql and \i this file.
+
+BEGIN;
+
+-- 1. leaf dependents
+TRUNCATE TABLE "GerbilPhotos"   CASCADE;
+TRUNCATE TABLE "WeightRecords"  CASCADE;
+TRUNCATE TABLE "HealthRecords"  CASCADE;
+
+-- 2. main import tables (Gerbils before Litters: Gerbil.LitterId FK)
+TRUNCATE TABLE "Gerbils"        CASCADE;
+TRUNCATE TABLE "Litters"        CASCADE;
+
+COMMIT;
+
+-- Verify (expected: 0 rows each)
+SELECT 'GerbilPhotos' AS tbl, COUNT(*) FROM "GerbilPhotos"
+UNION ALL SELECT 'WeightRecords',  COUNT(*) FROM "WeightRecords"
+UNION ALL SELECT 'HealthRecords',  COUNT(*) FROM "HealthRecords"
+UNION ALL SELECT 'Gerbils',        COUNT(*) FROM "Gerbils"
+UNION ALL SELECT 'Litters',        COUNT(*) FROM "Litters";