feat(bank): multi-bank chequera — required bankAccountId, per-account scoping

The office keeps more than one operating account (Utilities banks in MXN,
Seguros in USD), but bank_transactions was a single implicit MXN register by
design. Adds Bank/BankAccount and makes every read and write in the module
scoped to exactly one account.

Schema:
- Bank / BankAccount. Currency is fixed per account and BankTransaction has
  no currency column of its own — a movement inherits its account's, the way
  a real bank account doesn't mix currencies.
- BankTransaction.bankAccountId, required. A movement with no known account
  isn't reconcilable against a statement.
- @@index([bankAccountId, transactionDate]): every read now filters by
  account and orders/groups by date.

Migration:
- backfill_bank_accounts.py seeds Scotiabank + "Utilities — Scotiabank (MXN)"
  and backfills all 22,669 existing rows onto it, then promotes the column to
  NOT NULL and attaches the FK. Standalone because prisma db push cannot add
  a required column to a populated table. Idempotent; re-running once a second
  account exists does not re-point rows.
- run_all.py runs it (both modes) before transform_bank.py, which now resolves
  the account by label and fails fast if it is missing.

API:
- ?bankAccountId= required on list/stats/facets/summary — not optional with an
  "all accounts" default, since summing an MXN and a USD register repeats the
  currency-collapsing mistake the billing module exists to prevent. Missing is
  400, unknown is 404.
- facets() had no account clause at all and summary() has two raw-SQL rollups;
  all three are now parameterised. Scoping only one of summary's queries would
  leave the year list and its drill-down describing different books.
- New bank/accounts + bank/banks sub-resource under a MANAGER
  bank:manage-accounts ability. currency is absent from the update DTO: booked
  movements are denominated in it, so editing would re-denominate history.
  Capture into a closed account is rejected.

Web:
- /banco gains an account picker (remembered per browser) and reads every
  figure in the selected account's currency; the "single currency (MXN)"
  doc-comment and the hardcoded MXN formatting are gone.
- New /banco/cuentas for banks and accounts. Accounts are closed, never
  deleted — the FK is required, so deleting one would destroy its register.
- /inicio's chequera card names the account it is reading instead of implying
  a single register.

Verified against dev + browser: a second USD account showed full read/write
isolation from the MXN register, whose totals were unchanged (22,669
movements, net 1,014,266.97).

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

apps/web/src/lib/api.ts

@@ -6,9 +6,11 @@ import type {
   BalanceFilter,
   BalanceListResponse,
   BalanceSort,
+  BankAccount,
   BankCleared,
   BankDirection,
   BankFacets,
+  BankInstitution,
   BankListResponse,
   BankSort,
   BankStats,
@@ -19,8 +21,11 @@ import type {
   BillingStats,
   BusinessLine,
   ByCheckResponse,
+  CreateBankAccountInput,
+  CreateBankInput,
   CreateBankMovementInput,
   CreateMovementInput,
+  UpdateBankAccountInput,
   ResolveOutstandingInput,
   CustomerDetail,
   CustomerInput,
@@ -609,7 +614,13 @@ export function getByCheck(checkNumber: string): Promise<ByCheckResponse> {
 
 /* ------------------------------------------------- Bank register (chequera) */
 
+/**
+ * Every read below is scoped to one chequera. `bankAccountId` is required, not
+ * defaulted to "all accounts": the office's registers are in different
+ * currencies, and a combined total would be a figure that never existed.
+ */
 export interface BankQuery {
+  bankAccountId: string;
   query?: string;
   page?: number;
   pageSize?: number;
@@ -622,7 +633,7 @@ export interface BankQuery {
 }
 
 export function listBankMovements(q: BankQuery): Promise<BankListResponse> {
-  const params = new URLSearchParams();
+  const params = new URLSearchParams({ bankAccountId: q.bankAccountId });
   if (q.query) params.set("query", q.query);
   if (q.page) params.set("page", String(q.page));
   if (q.pageSize) params.set("pageSize", String(q.pageSize));
@@ -631,20 +642,78 @@ export function listBankMovements(q: BankQuery): Promise<BankListResponse> {
   if (q.from) params.set("from", q.from);
   if (q.to) params.set("to", q.to);
   if (q.sort) params.set("sort", q.sort);
-  const qs = params.toString();
-  return apiFetch<BankListResponse>(`/bank${qs ? `?${qs}` : ""}`);
+  return apiFetch<BankListResponse>(`/bank?${params.toString()}`);
 }
 
-export function getBankStats(): Promise<BankStats> {
-  return apiFetch<BankStats>("/bank/stats");
+export function getBankStats(bankAccountId: string): Promise<BankStats> {
+  return apiFetch<BankStats>(
+    `/bank/stats?bankAccountId=${encodeURIComponent(bankAccountId)}`,
+  );
 }
 
-export function getBankFacets(): Promise<BankFacets> {
-  return apiFetch<BankFacets>("/bank/facets");
+export function getBankFacets(bankAccountId: string): Promise<BankFacets> {
+  return apiFetch<BankFacets>(
+    `/bank/facets?bankAccountId=${encodeURIComponent(bankAccountId)}`,
+  );
 }
 
-export function getBankSummary(year?: number): Promise<BankSummary> {
-  return apiFetch<BankSummary>(`/bank/summary${year ? `?year=${year}` : ""}`);
+export function getBankSummary(
+  bankAccountId: string,
+  year?: number,
+): Promise<BankSummary> {
+  const params = new URLSearchParams({ bankAccountId });
+  if (year) params.set("year", String(year));
+  return apiFetch<BankSummary>(`/bank/summary?${params.toString()}`);
+}
+
+/* --------------------------------------------- Chequera accounts (catalog) */
+
+/** The account picker's source. Includes closed accounts, which stay readable. */
+export function listBankAccounts(): Promise<BankAccount[]> {
+  return apiFetch<BankAccount[]>("/bank/accounts");
+}
+
+export function listBankInstitutions(): Promise<BankInstitution[]> {
+  return apiFetch<BankInstitution[]>("/bank/banks");
+}
+
+export function createBankInstitution(
+  input: CreateBankInput,
+): Promise<BankInstitution> {
+  return apiFetch<BankInstitution>("/bank/banks", {
+    method: "POST",
+    body: JSON.stringify(input),
+  });
+}
+
+export function updateBankInstitution(
+  id: string,
+  input: Partial<CreateBankInput>,
+): Promise<BankInstitution> {
+  return apiFetch<BankInstitution>(`/bank/banks/${id}`, {
+    method: "PATCH",
+    body: JSON.stringify(input),
+  });
+}
+
+export function createBankAccount(
+  input: CreateBankAccountInput,
+): Promise<unknown> {
+  return apiFetch("/bank/accounts", {
+    method: "POST",
+    body: JSON.stringify(input),
+  });
+}
+
+/** No `currency` — an account's booked movements are denominated in it. */
+export function updateBankAccount(
+  id: string,
+  input: UpdateBankAccountInput,
+): Promise<unknown> {
+  return apiFetch(`/bank/accounts/${id}`, {
+    method: "PATCH",
+    body: JSON.stringify(input),
+  });
 }
 
 /** Append a new chequera movement. Booked rows are never edited — fix mistakes

apps/web/src/lib/types.ts

@@ -19,6 +19,7 @@ export type Ability =
   | "ledger:void"
   | "bank:create"
   | "bank:void"
+  | "bank:manage-accounts"
   | "lookup:manage"
   | "user:manage"
   | "db:manage";
@@ -1001,12 +1002,57 @@ export interface CustomerInput {
 /* ------------------------------------------------- Bank register (chequera) */
 
 /**
- * The office's own checking account. Single-currency (MXN) and with no customer
- * link — see `bank.service.ts`. Positive is a deposit, negative a payment, and
- * exactly zero a cancelled cheque.
+ * The office's own checking accounts — one register per chequera, no customer
+ * link. See `bank.service.ts`. Positive is a deposit, negative a payment, and
+ * exactly zero a cancelled cheque. Every figure below belongs to exactly one
+ * `BankAccount` and is denominated in that account's currency; two accounts'
+ * figures are never combined.
  */
 export type BankDirection = "income" | "expense" | "void";
 
+/** A bank the office holds chequeras at. */
+export interface BankInstitution {
+  id: string;
+  name: string;
+  /** "MX" | "US" — informational. */
+  country: string | null;
+}
+
+/** One chequera. Its `currency` is what every figure on the page is read in. */
+export interface BankAccount {
+  id: string;
+  label: string;
+  currency: Currency;
+  /** Soft hint about which line of business it serves; never enforced. */
+  businessLine: TransactionDomain | null;
+  /** Closed accounts stay readable but take no new movements. */
+  active: boolean;
+  bankId: string;
+  bankName: string;
+  bankCountry: string | null;
+}
+
+export interface CreateBankInput {
+  name: string;
+  country?: string;
+}
+
+export interface CreateBankAccountInput {
+  bankId: string;
+  label: string;
+  /** Fixed at creation — an account's booked history is denominated in it. */
+  currency: Currency;
+  businessLine?: TransactionDomain;
+  active?: boolean;
+}
+
+export interface UpdateBankAccountInput {
+  bankId?: string;
+  label?: string;
+  businessLine?: TransactionDomain;
+  active?: boolean;
+}
+
 export type BankCleared = "cleared" | "pending";
 
 export type BankSort =
@@ -1038,8 +1084,10 @@ export interface BankListItem {
 }
 
 /** Payload for POST /bank — a new chequera movement. Sign convention: positive
- *  = ingreso, negative = egreso. MXN only. */
+ *  = ingreso, negative = egreso. The currency comes from the account. */
 export interface CreateBankMovementInput {
+  /** Which chequera it lands in. Required. */
+  bankAccountId: string;
   amount: number;
   transactionDate: string;
   concept?: string;