fix(cash-accounts): rebind movable transactions when remapping a PSD2 ledger (#2023)

When a PSD2 remap collides with an overflow duplicate cash account (1931 next to a promoted 1930), the unbooked, unmatched, non-anchored transactions on the duplicate are rebound onto the promoted row before the duplicate is resolved, so booking stops proposing the dead ledger. Rows that are booked or anchored via transaction_voucher_links / invoice_payments / supplier_invoice_payments stay put and the duplicate is demoted (never deleted) while any remain, as before. Supersedes #1756.

Co-authored-by: Daniel Stenborg <daniel@stenborg.se>

DECISIONS.md

@@ -1338,4 +1338,5 @@ One line per decision: `[YYYY-MM-DD] <decision>: <why>`. Appended by agents and
 [2026-08-28] /migrate SIE guard skips company-info-only runs (all entity flags false) and the wizard derives "SIE already imported" from the preview OR this session's successful /import-sie results: company info writes no accounts, balances or subledger rows, so the BFL rationale does not apply; and the one-shot preview went stale after phase 1 succeeded and phase 2 failed, falsely blocking an entities-only retry (#2000 review).
 [2026-08-28] get_vat_ruta_source_lines (the VAT ruta drill-down) now applies the same four exclusions as get_vat_declaration_totals (the filed figure): posted closing entries, source_type 'vat_settlement', the two kontantmetod year-end reversals, and settlement-SHAPED entries (a line on a ruta account plus a line on 2650/1650). It previously filtered on company, status and date only, so expanding a ruta listed verifikat that are not in the number it claims to explain, with no total on the panel to reveal the mismatch. Measured on prod 2026-08-28: 322 posted/reversed entries carrying 26xx lines across 214 companies sit in those excluded classes. A momsdeklaration is räkenskapsinformation (BFL 5 kap.) and this drill-down is what substantiates a filed figure, so the two must agree exactly. The exclusion CTEs are lifted VERBATIM from the figure rather than re-derived: any divergence reintroduces exactly this bug, and an identical copy is easy to diff when the figure changes. Settlement-shape is detected against journal_entry_lines directly instead of through the figure's vat_lines CTE, which is EQUIVALENT not a shortcut (p_ruta_accounts = VAT_ACCOUNTS and p_net_accounts = ['2650','1650'] are both strict subsets of the figure's p_accounts, so restricting to vat_lines first cannot change which entries match); that keeps p_accounts meaning "the accounts of the ruta being expanded" without a fourth account parameter. opening_balance entries are deliberately NOT excluded: the figure exempts them from `shaped`, which keeps their lines IN the totals, so dropping them here would break the equality in the other direction (pinned by its own test). VAT_ACCOUNTS is now exported from lib/reports/vat-declaration.ts so the route detects shape from the same list the figure uses; a second copy is what let the two disagree. DROP + CREATE OR REPLACE, not CREATE OR REPLACE alone: the signature gains p_ruta_accounts/p_net_accounts and adding parameters registers a second overload PostgREST cannot choose between (trap documented in 20260421140000); OR REPLACE on the new arity keeps the file re-runnable. Verified the new pg test actually catches the bug by reinstalling the old body and watching 3 of 4 tests fail with the real misreporting (2611: drill-down 250/240 vs figure 0/200), then restoring.
 [2026-08-28] Bankavstamning NULL-link fix scoped to transfer legs with contradicting sign (20260828220000): the naive rule (NULL counts only for the primary account) and the formula-only variant (drop far-leg-settled vouchers from unexplained) were both simulated against prod and rejected; the naive rule worsened 4 of 11 affected cards (worst -37 000 kr false alarm on single-leg vouchers with no user action available), the formula variant blew up healthy cards by up to 474 550 kr. The shipped three-condition rule changes 24 vouchers on 7 cards in 6 companies, all verified per-card.
+[2026-08-29] PR #1756 replacement (rebind on PSD2 remap, amends the 2026-07-09 #916 entry): when upsertFromPsd2 resolves a duplicate row for the same connection+uid, the duplicate's MOVABLE transactions (unbooked, unmatched, not anchored via transaction_voucher_links or a payment row: the #1570 single-row move gate) are rebound onto the promoted row BEFORE the duplicate is resolved, so categorize/booking proposes the ledger the user just mapped instead of the overflow slot; a duplicate that still holds booked or anchored rows is demoted to manual as before and never deleted (their vouchers carry the old 19xx line, and the #1643 orphan guards handle the released twin). The contributor's unconditional rebind-all-then-delete was narrowed for that reason.
 [2026-08-29] Database errors now keep their SQLSTATE: new lib/errors/db-error.ts (dbError/errorCauseTag), applied at the 54 `throw new Error(\`Database error: ${err.message}\`)` sites in the MCP server AND, far more importantly, at lib/supabase/fetch-all.ts:74 where `throw new Error(error.message)` was the single highest-traffic strip point in the codebase (31 callers; every paginated read). isTransientFailure() checks the driver code FIRST and 57014 (statement timeout) is already in TRANSIENT_SQLSTATES, so discarding it turned a retryable timeout into UNKNOWN_ERROR ("Något gick fel. Försök igen."), which an agent cannot dispatch on. Traced end to end: gnubok_query_journal -> fetchEntryLines -> fetchAllRows (code stripped here) -> the tool's own sanitizeDbError, which ALREADY had a correct TRANSIENT_ERROR branch with a "retry or narrow with date_from/date_to" hint that could never fire because getStructuredError saw an anonymous Error. Measured on prod over 60 days with bot actors excluded: 1 024 real-agent failures, 645 UNKNOWN_ERROR across 60 actors and 57 companies; query_journal failed 164 times at p50 8 110 ms while every other failing tool sat at 1-315 ms; 82 retry streaks, 462 wasted repeat calls, 53.1% of error calls inside a streak. fetch-all passes context=null so the driver message stays VERBATIM (sanitizeDbError and other callers match on the existing text; this change adds the code, it does not reword). Attaching `code` is safe because extractCode() only accepts /^[A-Z_]+$/ and every SQLSTATE/PostgREST code contains digits, so it cannot hijack the application error registry (pinned by a test). dbError also never renders the literal "undefined": a driver-level failure with no message produced "Database error: undefined", the string that made these unsearchable. errorCauseTag() returns a PII-safe SQLSTATE for telemetry; the raw driver message can quote row values in a constraint violation and belongs in the server log, never in event_log. NOT ratcheted: check:types reports 538 vs baseline 539 because main fixed an unrelated error in own-account-detector.test.ts after the baseline was set; the gate only fails on an INCREASE, so the baseline is left alone rather than adding unrelated churn to this diff.