fix: BankID fallback, bank import fixes, account deletion (#216)

* fix: BankID graceful fallback, bank import fixes, and account deletion

- BankID: surface service_unavailable state in login/register with password
  fallback messaging; structured error codes in tic extension; poll failure
  counter in BankIdAuth avoids infinite retry when TIC API is down.
- Transactions: allow deleting unbooked bank-synced and imported transactions
  (only posted entries remain protected); detect reconnect duplicates by also
  checking unbooked bank-synced rows in content-based dedup.
- Enable Banking: key external_id by account iban/uid instead of connection id
  so reconnects don't create duplicates.
- Bank import: detect SEB privatbanken CSV variant (Bokföringsdatum /
  Valutadatum headers) via regex.
- Banking settings: replace full-screen sync loader with toast notifications.
- delete_user_account: raise statement_timeout, pre-clear NO ACTION FK
  references, and disable audit/immutability triggers during CASCADE.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

* fix: address Greptile review — ingest dedup scoping and migration EXCEPTION handler

- ingest: split buildExistingTransactionMap into two maps. Booked rows
  (any source) remain consumed by any incoming raw transaction, but
  unbooked enable_banking slots are only consumed when the incoming raw
  transaction is also enable_banking. This preserves reconnect dedup
  while preventing false positives where a pending bank-synced row
  silently blocks a legitimately separate CSV row with the same
  date/amount.
- delete_user_account: add EXCEPTION WHEN OTHERS handler that re-enables
  every legally required enforcement trigger before re-raising. Postgres
  transactional DDL already rolls back on abort, but the explicit guard
  makes the intent unambiguous and covers sub-transaction edge cases so
  enforcement triggers are never left disabled.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

components/transactions/TransactionInboxCard.tsx

@@ -60,7 +60,7 @@ export default function TransactionInboxCard({
   const isUncategorized = transaction.is_business === null && !transaction.journal_entry_id
   const showCheckbox = isBatchMode && isUncategorized
   const hasDocumentMatch = !!transaction.matched_inbox_item
-  const isManualTransaction = !transaction.bank_connection_id && !transaction.import_source && !transaction.journal_entry_id
+  const isDeletable = !transaction.journal_entry_id
 
   function handleSuggestionClick(suggestion: SuggestedCategory) {
     if (onOpenQuickReview) {
@@ -251,8 +251,8 @@ export default function TransactionInboxCard({
                 Välj mall...
               </Button>
 
-              {/* Delete button — only for manually added, unbooked transactions */}
-              {isManualTransaction && onDelete && (
+              {/* Delete button — available for all unbooked transactions */}
+              {isDeletable && onDelete && (
                 <Button
                   size="sm"
                   variant="ghost"