feat(reconciliation): manual adapter for the whole balance sheet (Reko bilagor, PR 1) (#1854)

* feat(reconciliation): manual adapter so the whole balance sheet is reconcilable and signable (Reko bilagor, PR 1)

Every class 1-2 account the bank and skattekonto adapters do not own now
appears on the Avstämning page under "Övriga balanskonton" with IB, movement
and UB through the balansdag, a system specification where one exists
(1510 kundreskontra, 2440 leverantörsreskontra, 2920/2940 semesterlöneskuld)
and, for every other account, the balance the signer states from their
underlag at sign-off. Same three doors as before: dashboard routes, v1 API
and the MCP tools take manual:<BAS> keys and an external_balance.

The ledger side is computed per fiscal period via generateTrialBalance,
never as an all-history sum: year-end re-books every balance account in an
opening_balance verifikat, so an all-history sum counts a closed year twice.

A stated external_balance is refused (EXTERNAL_BALANCE_NOT_ALLOWED) wherever
the system already has an outside truth, so it can never hide a difference.

No migration: account_reconciliations already accepts manual:NNNN keys.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RvFveUpbdPBXdm7f5FEYoz

* chore(api-skill): regenerate banking reference for the sign-off external_balance field

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RvFveUpbdPBXdm7f5FEYoz

---------

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

lib/pending-operations/commit.ts

@@ -6070,6 +6070,7 @@ async function commitReconciliationSignoff(
         through_date: throughDate,
         note: (params.note as string | null | undefined) ?? null,
         force: params.force === true,
+        external_balance: typeof params.external_balance === 'number' ? params.external_balance : null,
       },
       { dryRun: false },
     )