fix(accounts): break AccountDao sortOrder ties by email

AccountDaoTest (added by #270's coverage lane) asserts email ordering,
but AccountDao.observeAll()/getAll() now order by the user-defined
sortOrder (#164) with no tiebreaker. Two accounts inserted via plain
upsert() both land on the default sortOrder (0), so they came back in
rowid/insertion order instead — failing the test deterministically on
CI (API 30 & 31): expected [ada, zed], got [zed, ada].

Add `email` as a secondary ORDER BY key. Real accounts always get
distinct sortOrders via insertAtEnd()/reorder(), so drag order is
untouched; only equal-sortOrder rows now fall back to a stable,
deterministic email order. This also matches the "rank by email"
convention already used to seed sortOrder in ACCOUNT_MIGRATION_1_2 and
AccountDataMigrator.copyAccountTables, so the existing coverage test
passes unchanged. No schema/migration change is needed since this
only edits a @Query string, not the entity.

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

app/src/main/kotlin/org/libremail/data/local/dao/AccountDao.kt

@@ -11,10 +11,17 @@ import org.libremail.data.local.entity.AccountEntity
 
 @Dao
 interface AccountDao {
-    @Query("SELECT * FROM accounts ORDER BY sortOrder")
+    /**
+     * Every listing surface (Settings, the drawer switcher, the unified-inbox filter chips) follows
+     * the user-defined [AccountEntity.sortOrder] (issue #164); `email` is only a tiebreaker for rows
+     * that share a sortOrder (e.g. inserted via plain [upsert] rather than [insertAtEnd]/[reorder]),
+     * so equal-sortOrder accounts still list in a stable, deterministic order.
+     */
+    @Query("SELECT * FROM accounts ORDER BY sortOrder, email")
     fun observeAll(): Flow<List<AccountEntity>>
 
-    @Query("SELECT * FROM accounts ORDER BY sortOrder")
+    /** See [observeAll] — same ordering: sortOrder, then email as a tiebreaker. */
+    @Query("SELECT * FROM accounts ORDER BY sortOrder, email")
     suspend fun getAll(): List<AccountEntity>
 
     @Query("SELECT * FROM accounts WHERE id = :id LIMIT 1")