feat(import): support Wise balance statements (#1368)

* feat(import): support Wise balance statements

* fix(import): fail closed on ambiguous Wise rows

* fix(import): guard Wise statement netted-fee assumption with running-balance continuity check

Swedish accounting review asked whether balance-statement Total fees is
netted into Amount. It is: Running Balance moves by exactly the signed
Amount per row, so a separate fee row would double-count the cost. Codify
the assumption with a pairwise continuity warning (order-agnostic, chain
resets across skipped rows) and document the decision.

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

* fix(api): cap bank-import validation payload and harden issue assertion

CodeRabbit review: bound the VALIDATION_ERROR issues array to 20 entries
with issue_count carrying the full total, so a large malformed file cannot
balloon the response or log sink. Gate stays format-agnostic on purpose:
error severity means do-not-ingest for every parser, and no non-Wise parser
emits per-row errors alongside parsed transactions today.

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

---------

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

DECISIONS.md

@@ -746,6 +746,8 @@ One line per decision: `[YYYY-MM-DD] <decision>: <why>`. Appended by agents and
 [2026-08-02] Out-of-order SIE IB resync requires exact date adjacency: the nearest later fiscal period can sit beyond a missing middle year, and replacing its authoritative IB with a non-adjacent UB would make that later period temporarily wrong until the gap was imported.
 [2026-08-03] Issue #1360 keeps EUR annual reports fail-closed at general eligibility rather than only digital filing: the ledger and annual-report model are SEK-denominated, so allowing a EUR profile to lock a paper version would mislabel SEK amounts; full EUR support requires a company accounting-currency model across the ledger, report builders, and iXBRL.
 [2026-08-03] Issue #1267 localizes the latest-posted-voucher label in the web views while PDF and spreadsheet exports remain Swedish: translating one export label would create mixed-language files, so full export localization stays a separate surface-wide change.
+[2026-08-03] Wise imports fail closed on refunded or unknown statuses, unknown directions, and cross-currency transaction-history rows: the available export contract cannot establish their signed balance effect, and v1 must not silently discard a business event. Ordinary balance-statement rows share the canonical wise_ID external ID with transaction history to prevent overlapping cross-format imports; only conversion legs with explicit Exchange From/To metadata add the statement currency because the same Wise ID represents one movement per balance.
+[2026-08-03] Wise balance-statement "Total fees" stays description-only, guarded by a running-balance continuity warning: Running Balance moves by exactly the signed Amount per row, so the fee is a breakdown of Amount and booking it separately (as wise.ts does for the "(after fees)" history export) would double-count the cost and desync the imported account from the real Wise balance.
 
 [2026-08-03] Shared format contracts centralised in lib/invariants/ (org number, BAS account number, ISO date, fiscal year), each with its rationale recorded next to the rule. Trigger: four Skatteverket/Bolagsverket-bound export paths (KU10, AGI, SRU redovisare, iXBRL preflight) each had their own idea of a valid organisationsnummer, so a company stored with a space or in 12-digit form could file AGI all year and fail at the arsredovisning deadline. normalizeOrgNumber moved from lib/company-lookup/ and isSaneDateString from lib/utils.ts; both old paths re-export. The iXBRL check-digit verdict is warn, not error: we do not block a statutory filing on a Luhn assumption unverified against a primary source. KU10 12-digit passthrough pinned by test, not changed (open domain question). ROT/RUT brf_org_number left alone: different documented contract. Ratchet guard 8 holds the remaining 114 inline copies.