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/api/src/bank/bank.service.ts

@@ -2,6 +2,12 @@ import { BadRequestException, Injectable, NotFoundException } from "@nestjs/comm
 import { Prisma } from "@jorgecuadros/database";
 import { PrismaService } from "../prisma/prisma.service";
 import { CreateBankMovementDto } from "./bank-movement.dto";
+import {
+  CreateBankAccountDto,
+  CreateBankDto,
+  UpdateBankAccountDto,
+  UpdateBankDto,
+} from "./bank-account.dto";
 
 /**
  * App-voided rows (voidedAt set) are reversed and must leave every
@@ -28,9 +34,18 @@ const NOT_VOIDED: Prisma.BankTransactionWhereInput = { voidedAt: null };
  *     expense and are excluded from both sides, the way the ~193 zero rows are
  *     in the customer ledger.
  *
- * SINGLE CURRENCY. Unlike the customer ledger there is no currency column here:
- * `bank_transactions` has none, and every `amountInWords` on the egreso side is
- * spelled out in PESOS. All figures in this module are MXN.
+ * ONE ACCOUNT AT A TIME, CURRENCY FROM THE ACCOUNT. The office now keeps more
+ * than one chequera (Utilities banks in MXN, Seguros in USD), so every read
+ * path here is scoped to exactly one `bankAccountId` — never "all accounts".
+ * There is deliberately no currency column on `bank_transactions`: a movement
+ * inherits its account's, the way a real bank account doesn't mix currencies.
+ * Callers must therefore pass an account id; an unscoped total would sum MXN
+ * and USD into a figure that never existed, the same mistake the billing
+ * module's per-currency rule exists to prevent.
+ *
+ * The 22,669 migrated rows are all SCOTHIA = the Utilities MXN account
+ * (backfilled by `migration/backfill_bank_accounts.py`), and their
+ * `amountInWords` on the egreso side is spelled out in PESOS accordingly.
  *
  * NO CATEGORY DIMENSION. `bank_transactions.categoryId` is NULL on all 22,354
  * rows and this module does not filter or group by it, because the data cannot
@@ -64,6 +79,8 @@ export type BankSort =
   | "reference";
 
 export interface BankListParams {
+  /** Which chequera to read. Required — see the module header. */
+  bankAccountId: string;
   query?: string;
   page: number;
   pageSize: number;
@@ -98,7 +115,9 @@ export class BankService {
   constructor(private readonly prisma: PrismaService) {}
 
   private where(p: BankListParams): Prisma.BankTransactionWhereInput {
-    const and: Prisma.BankTransactionWhereInput[] = [];
+    const and: Prisma.BankTransactionWhereInput[] = [
+      { bankAccountId: p.bankAccountId },
+    ];
 
     if (p.query && p.query.trim()) {
       const q = p.query.trim();
@@ -124,7 +143,9 @@ export class BankService {
       });
     }
 
-    return and.length ? { AND: and } : {};
+    // Never empty: the account clause above is always present, so no read can
+    // accidentally span every chequera.
+    return { AND: and };
   }
 
   private orderBy(
@@ -233,22 +254,25 @@ export class BankService {
     };
   }
 
-  /** Top-line figures for the bank page header. */
-  async stats() {
+  /** Top-line figures for the bank page header, for one chequera. */
+  async stats(bankAccountId: string) {
+    const account = { bankAccountId };
     const [count, bounds, pending, transferred, totals] = await Promise.all([
-      this.prisma.bankTransaction.count({ where: NOT_VOIDED }),
+      this.prisma.bankTransaction.count({
+        where: { AND: [account, NOT_VOIDED] },
+      }),
       this.prisma.bankTransaction.aggregate({
-        where: NOT_VOIDED,
+        where: { AND: [account, NOT_VOIDED] },
         _min: { transactionDate: true },
         _max: { transactionDate: true },
       }),
       this.prisma.bankTransaction.count({
-        where: { AND: [{ cleared: false }, NOT_VOIDED] },
+        where: { AND: [account, { cleared: false }, NOT_VOIDED] },
       }),
       this.prisma.bankTransaction.count({
-        where: { AND: [{ transferred: true }, NOT_VOIDED] },
+        where: { AND: [account, { transferred: true }, NOT_VOIDED] },
       }),
-      this.totalsFor({}),
+      this.totalsFor(account),
     ]);
 
     return {
@@ -261,14 +285,16 @@ export class BankService {
     };
   }
 
-  /** Year list for the period filter, newest first. */
-  async facets() {
+  /** Year list for the period filter, newest first, for one chequera. */
+  async facets(bankAccountId: string) {
+    // Tagged-template `$queryRaw`: the interpolation below is a bound
+    // parameter, not string concatenation.
     const years = await this.prisma.$queryRaw<
       { year: number; count: bigint | number | string }[]
     >`
       SELECT YEAR(transactionDate) AS year, COUNT(*) AS count
       FROM bank_transactions
-      WHERE voidedAt IS NULL
+      WHERE voidedAt IS NULL AND bankAccountId = ${bankAccountId}
       GROUP BY year
       ORDER BY year DESC
     `;
@@ -287,8 +313,12 @@ export class BankService {
    * `BAN` table holds only the bank's name), so the register starts at zero on
    * its first row in 2013 and the running figure is the net movement since
    * then. Labelled as such in the UI so it is never read as a statement balance.
+   *
+   * Both rollups take the SAME `bankAccountId`. Scoping only one of them would
+   * leave the year list and its month drill-down describing different books —
+   * wrong in a way that still looks right.
    */
-  async summary(year?: number) {
+  async summary(bankAccountId: string, year?: number) {
     const years = await this.prisma.$queryRaw<PeriodRow[]>`
       SELECT
         YEAR(transactionDate)                                AS period,
@@ -297,7 +327,7 @@ export class BankService {
         SUM(CASE WHEN amount < 0 THEN amount ELSE 0 END)     AS expense,
         SUM(amount)                                          AS net
       FROM bank_transactions
-      WHERE voidedAt IS NULL
+      WHERE voidedAt IS NULL AND bankAccountId = ${bankAccountId}
       GROUP BY period
       ORDER BY period ASC
     `;
@@ -311,7 +341,9 @@ export class BankService {
             SUM(CASE WHEN amount < 0 THEN amount ELSE 0 END)   AS expense,
             SUM(amount)                                        AS net
           FROM bank_transactions
-          WHERE YEAR(transactionDate) = ${year} AND voidedAt IS NULL
+          WHERE YEAR(transactionDate) = ${year}
+            AND voidedAt IS NULL
+            AND bankAccountId = ${bankAccountId}
           GROUP BY period
           ORDER BY period ASC
         `
@@ -365,13 +397,135 @@ export class BankService {
     };
   }
 
+  // --- accounts -------------------------------------------------------------
+
+  /**
+   * Every chequera, closed ones included — a closed account still has to be
+   * selectable to read its history, it just isn't offered for new captures.
+   */
+  async listAccounts() {
+    const rows = await this.prisma.bankAccount.findMany({
+      orderBy: [{ active: "desc" }, { label: "asc" }],
+      select: {
+        id: true,
+        label: true,
+        currency: true,
+        businessLine: true,
+        active: true,
+        bank: { select: { id: true, name: true, country: true } },
+      },
+    });
+    return rows.map((a) => ({
+      id: a.id,
+      label: a.label,
+      currency: a.currency,
+      businessLine: a.businessLine,
+      active: a.active,
+      bankId: a.bank.id,
+      bankName: a.bank.name,
+      bankCountry: a.bank.country,
+    }));
+  }
+
+  async listBanks() {
+    return this.prisma.bank.findMany({
+      orderBy: { name: "asc" },
+      select: { id: true, name: true, country: true },
+    });
+  }
+
+  /**
+   * Resolve an account id from a request, or reject. Every read route funnels
+   * through this so a bad/missing id is a 400 rather than a silently empty
+   * register that reads as "this account has no movements".
+   */
+  async requireAccount(bankAccountId: string | undefined) {
+    if (!bankAccountId || !bankAccountId.trim())
+      throw new BadRequestException("Falta la cuenta bancaria (bankAccountId)");
+    const account = await this.prisma.bankAccount.findUnique({
+      where: { id: bankAccountId },
+      select: { id: true, label: true, currency: true, active: true },
+    });
+    if (!account)
+      throw new NotFoundException(`Cuenta bancaria ${bankAccountId} no existe`);
+    return account;
+  }
+
+  async createBank(dto: CreateBankDto) {
+    return this.prisma.bank.create({
+      data: { name: dto.name.trim(), country: dto.country?.trim() || null },
+    });
+  }
+
+  async updateBank(id: string, dto: UpdateBankDto) {
+    await this.getBankOr404(id);
+    return this.prisma.bank.update({
+      where: { id },
+      data: {
+        ...(dto.name !== undefined ? { name: dto.name.trim() } : {}),
+        ...(dto.country !== undefined
+          ? { country: dto.country.trim() || null }
+          : {}),
+      },
+    });
+  }
+
+  private async getBankOr404(id: string) {
+    const bank = await this.prisma.bank.findUnique({
+      where: { id },
+      select: { id: true },
+    });
+    if (!bank) throw new NotFoundException(`Banco ${id} no existe`);
+    return bank;
+  }
+
+  async createAccount(dto: CreateBankAccountDto) {
+    await this.getBankOr404(dto.bankId);
+    return this.prisma.bankAccount.create({
+      data: {
+        bankId: dto.bankId,
+        label: dto.label.trim(),
+        currency: dto.currency,
+        businessLine: dto.businessLine ?? null,
+        active: dto.active ?? true,
+      },
+    });
+  }
+
+  /**
+   * `currency` is intentionally absent from the update DTO: the movements
+   * already booked in this account are denominated in it, so changing it would
+   * silently re-denominate history rather than convert it.
+   */
+  async updateAccount(id: string, dto: UpdateBankAccountDto) {
+    await this.requireAccount(id);
+    if (dto.bankId !== undefined) await this.getBankOr404(dto.bankId);
+    return this.prisma.bankAccount.update({
+      where: { id },
+      data: {
+        ...(dto.bankId !== undefined ? { bankId: dto.bankId } : {}),
+        ...(dto.label !== undefined ? { label: dto.label.trim() } : {}),
+        ...(dto.businessLine !== undefined
+          ? { businessLine: dto.businessLine }
+          : {}),
+        ...(dto.active !== undefined ? { active: dto.active } : {}),
+      },
+    });
+  }
+
   // --- writes (append + void) -----------------------------------------------
 
   async createMovement(dto: CreateBankMovementDto) {
     const date = new Date(dto.transactionDate);
     if (isNaN(date.getTime())) throw new BadRequestException("Fecha inválida");
+    const account = await this.requireAccount(dto.bankAccountId);
+    if (!account.active)
+      throw new BadRequestException(
+        `La cuenta "${account.label}" está cerrada; no admite movimientos nuevos.`,
+      );
     return this.prisma.bankTransaction.create({
       data: {
+        bankAccountId: account.id,
         amount: dto.amount,
         transactionDate: date,
         concept: dto.concept,