fix(db): drop mint_counters + reservations in cleanAll

cleanAll only dropped transactions/proofs/dbversion, leaving the
mint_counters and reservations tables (added by later migrations) behind.
A wallet wipe would keep stale derivation counters, which the next launch
would hydrate. Drop them too (IF EXISTS, so an old DB lacking them doesn't
abort the atomic batch). Tables are recreated on next launch via the
IF-NOT-EXISTS schema bootstrap.

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

src/services/db/instance.ts

@@ -59,6 +59,10 @@ export const cleanAll = function () {
     ['DROP TABLE transactions'],
     ['DROP TABLE proofs'],
     ['DROP TABLE dbversion'],
+    // IF EXISTS: these tables were added by later migrations, so a very old DB
+    // may lack them; without the guard a missing table aborts the atomic batch.
+    ['DROP TABLE IF EXISTS reservations'],
+    ['DROP TABLE IF EXISTS mint_counters'],
   ] as SQLBatchTuple[]
 
   try {