feat(reconciliation): account-keyed engine: one bridge for bank and skattekonto (#1813)

* feat(reconciliation): skattekonto bridge engine, sync-time twin proposals, account-keyed facade

The engine half of the reconciliation page (design: Avstämningsmotorn).

- lib/reconciliation/skattekonto-reconciliation.ts: getSkattekontoReconciliationStatus
  anchors at the saldo snapshot and returns the bridge (saldo hos Skatteverket,
  händelser som saknas, 1630-rader utan händelse, ignorerade, ingående skillnad,
  bokfört), the item buckets the page shows (proposed, unmatched external,
  unmatched ledger, matched, ignored, upcoming), opening_difference,
  unexplained_difference (0,00 by construction when data is consistent),
  dead-link handling (a link to a reversed/draft entry counts as unlinked and is
  flagged), awaiting_external for ledger lines within 5 days of the snapshot,
  staleness, and a window that scopes item lists without hiding older rows.
  Core reads skattekonto_transactions and the extension's snapshot row directly;
  no @/extensions import.
- lib/reconciliation/gl-balance.ts: one ledger-balance helper with the
  trial-balance predicate status IN (posted, reversed). The drift check summed
  posted only, which misstated 1630 for any company with a storno on the account;
  skattekonto-drift.ts now delegates to the helper.
- Proposals at sync: migration 20260823120000 adds suggested_journal_entry_id /
  suggested_at (ON DELETE SET NULL, partial index on open rows); the sync calls
  refreshSkattekontoProposals after the upsert. findMatchSuggestionsBulk now
  assigns one-to-one across rows (AGI period first, then nearest date) and falls
  back to an entry whose 1630 lines net to the amount (split lines); a proposal
  is never a link.
- lib/reconciliation/service.ts + schemas.ts: the account-keyed facade
  (bank:<cash_account_id> | skattekonto | manual:NNNN) with listReconciliationAccounts
  (enabled cash accounts folded per IBAN, skattekonto when configured) and
  getAccountStatus dispatching to the bank engine or the new one; shared Zod
  shapes for the v1 registry, MCP schemas and the UI (PR 2).

Tests: identity on a mixed fixture, storno pair, stale snapshot, awaiting window,
window scoping, failed ledger read, live-linked entries never proposed; matcher
one-to-one and split-line cases; proposal refresh writes/clears; service
dedupe and dispatch. No UI in this PR.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix(reconciliation): roundOre instead of inline öre rounding (guard ratchet)

The antipattern ratchet counts Math.round(x*100)/100; the new engine used it in
five places. Switch to roundOre from @/lib/money and ratchet the baseline down
by the three occurrences this removes net of the matcher rewrite.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

DECISIONS.md

@@ -1176,3 +1176,4 @@ One line per decision: `[YYYY-MM-DD] <decision>: <why>`. Appended by agents and
 [2026-08-24] Assistant empty answer is a typed failure (EmptyModelAnswerError, 502 'Assistenten gav inget svar. Försök igen.'), one manual retry, NO auto-retry: the silent 200 with an empty answer was the 'Tänker then nothing' bug after the RIP-3 cutover (1500-token cap on /api/agent/ask), and auto-retry would double model spend while hiding the regression. Related deliberate request-shape change: anthropic-family's step-exhausted fallback now keeps tools with tool_choice none, because replaying a transcript containing tool_use/tool_result without declaring tools is rejected by the Messages API (the old shape 400ed every step-exhausted answer). general.help stays on the single-call runtime (founder decision); the fix raises headroom to 5400 tokens and surfaces the failure instead.
 [2026-08-24] Issue #1820 self-billed credit fix: creditConfirmNumber()/originalRef fall back invoice_number -> external_invoice_number (typed 400 INVOICE_CREDIT_NO_NUMBER if both null) instead of relaxing the DB numbering constraint or dropping the type-the-number confirm step; the confirm step stays (dropping it is a founder call). The invoice-date Forval chip surfaces in ALL editor modes, not only self-billed: the silent today-default exists in every mode and the chip line already carries the due date. In self-billed mode fakturadatum + mottagningsdatum render uncollapsed next to the external number (transcription fields, not defaults); the panel rows are hidden there because registering the same RHF field twice desyncs the inputs. The v1 credit route's existing id-slice fallback was left unchanged (public API behavior).
 [2026-08-24] No-IBAN reconnect pairing (issue #1709) uses only per-currency exactly-one-each-side elimination, deliberately WITHOUT name equality: ASPSPs reformat product names between consents, so requiring it would silently disable the fix for the banks that need it, while the one-per-currency guard already bounds a mis-pair to skipping rows whose account+date+amount+occurrence all collide. upsertFromPsd2 needed no change: its explicit reuse_cash_account_id promote path already covers a same-connection holder, so the fix only names the paired row from the callback.
+[2026-08-23] Reconciliation engine (PR 1): the skattekonto status engine lives in core lib/reconciliation (reads the core table + the extension snapshot row in extension_data directly) instead of in the skatteverket extension: core must never import @/extensions/*, and the reconciliation facade must work with zero extensions; the matcher stays in the extension and writes its proposals to the row at sync time. Proposals are propose-only (suggested_journal_entry_id is never a link); the same per-entry one-to-one assignment replaces per-row "exactly one candidate". Ledger balances everywhere in reconciliation use the trial-balance predicate status IN (posted, reversed): the drift check summed posted only, which misstated 1630 for every company with a storno on the account.