Add music store seed preset and repair data reset script

- music-store-seed.ts: 52 templates covering strings, brass, woodwinds,
  guitar, plus music-specific tickets and a school band batch
- reset-repairs.ts: clears all repair data for switching between presets
- New scripts: bun run db:seed-music, bun run db:seed-reset-repairs

packages/backend/src/db/seeds/reset-repairs.ts

@@ -0,0 +1,37 @@
+/**
+ * Reset repair data — clears all repair tickets, batches, templates, notes, and line items.
+ * Run: bun run db:seed-reset-repairs
+ *
+ * Use this before switching between seed presets (e.g. generic → music store).
+ */
+import postgres from 'postgres'
+
+const DB_URL = process.env.DATABASE_URL ?? 'postgresql://lunarfront:lunarfront@localhost:5432/lunarfront'
+const sql = postgres(DB_URL)
+
+async function reset() {
+  console.log('Resetting repair data...')
+
+  const notes = await sql`DELETE FROM repair_note RETURNING id`
+  console.log(`  Deleted ${notes.length} notes`)
+
+  const lineItems = await sql`DELETE FROM repair_line_item RETURNING id`
+  console.log(`  Deleted ${lineItems.length} line items`)
+
+  const tickets = await sql`DELETE FROM repair_ticket RETURNING id`
+  console.log(`  Deleted ${tickets.length} tickets`)
+
+  const batches = await sql`DELETE FROM repair_batch RETURNING id`
+  console.log(`  Deleted ${batches.length} batches`)
+
+  const templates = await sql`DELETE FROM repair_service_template RETURNING id`
+  console.log(`  Deleted ${templates.length} templates`)
+
+  console.log('\nRepair data cleared. Run a seed to repopulate.')
+  await sql.end()
+}
+
+reset().catch((err) => {
+  console.error('Reset failed:', err)
+  process.exit(1)
+})