fix(encryption): align stale account encrypted flags with plaintext names

A handful of legacy accounts are still flagged encrypted=true while their
name is stored in plaintext (name_iv is null). The client-side decrypt-
migration only clears the flag for accounts with an actually-encrypted name,
so these stale flags never resolve and keep the user perpetually counted as
"has encrypted accounts". Backfill the flag to match reality.

Transaction decryption is unaffected: it is driven by each transaction's
description_iv / notes_iv, not by this account flag.

database/migrations/2026_06_20_105609_align_accounts_encrypted_flag_with_plaintext_names.php

@@ -0,0 +1,35 @@
+<?php
+
+use Illuminate\Database\Migrations\Migration;
+use Illuminate\Support\Facades\DB;
+
+return new class extends Migration
+{
+    /**
+     * Some legacy accounts are still flagged `encrypted = true` even though
+     * their name is stored in plaintext (`name_iv` is null). The client-side
+     * decrypt-migration only clears the flag for accounts whose name is
+     * actually encrypted, so these stale flags would never resolve on their
+     * own and keep the user perpetually counted as "has encrypted accounts".
+     * Align the flag with reality: an account with no `name_iv` is not
+     * encrypted. Transaction decryption is unaffected — it is driven by each
+     * transaction's `description_iv` / `notes_iv`, not by this flag.
+     */
+    public function up(): void
+    {
+        DB::table('accounts')
+            ->where('encrypted', true)
+            ->whereNull('name_iv')
+            ->update(['encrypted' => false]);
+    }
+
+    /**
+     * Irreversible: once flipped, a migration-corrected account is
+     * indistinguishable from an account that was always plaintext, so blanket
+     * re-flagging would wrongly encrypt legitimately unencrypted accounts.
+     */
+    public function down(): void
+    {
+        //
+    }
+};

tests/Feature/AlignAccountsEncryptedFlagMigrationTest.php

@@ -0,0 +1,21 @@
+<?php
+
+use App\Models\Account;
+
+function runAlignEncryptedFlagMigration(): void
+{
+    $migration = require database_path('migrations/2026_06_20_105609_align_accounts_encrypted_flag_with_plaintext_names.php');
+    $migration->up();
+}
+
+it('clears the encrypted flag only for accounts whose name is plaintext', function () {
+    $staleFlag = Account::factory()->create(['encrypted' => true, 'name_iv' => null]);
+    $encryptedName = Account::factory()->create(['encrypted' => true, 'name_iv' => str_repeat('a', 16)]);
+    $alreadyPlaintext = Account::factory()->create(['encrypted' => false, 'name_iv' => null]);
+
+    runAlignEncryptedFlagMigration();
+
+    expect($staleFlag->fresh()->encrypted)->toBeFalse()
+        ->and($encryptedName->fresh()->encrypted)->toBeTrue()
+        ->and($alreadyPlaintext->fresh()->encrypted)->toBeFalse();
+});