feat(ledger,bank): append + void write API, voided excluded from totals (plan phase 5 API)

Transactions and the bank register become append-only with a void
(reversal) action — never edited or hard-deleted. This is the API half of
phase 5; the capture/void web UI is the remaining piece.

Schema:
- Transaction and BankTransaction gain voidedAt + voidedById. A non-null
  voidedAt reverses the row. Pushed to dev.

Correctness (the high-stakes part):
- Every aggregate excludes voided rows: billing movements totals, the raw
  balances SQL, stats (groupBy + the sides/crossLine raw subqueries +
  first/last), facets (types/sources/years); the statement's running
  balance freezes on a voided row and its per-currency/per-domain/per-type
  summaries skip them; customers.detail and property owner-ledger groupBy;
  and every bank total (totalsFor, stats counts/bounds, facets + summary
  raw SQL). List views still return voided rows with a `voided` flag so
  the UI can strike them through.
- Bank's legacy zero-amount "void" cheques are unchanged and distinct from
  app voids (voidedAt).

API:
- POST /billing + POST /billing/:id/void (ledger:create / ledger:void);
  POST /bank + POST /bank/:id/void (bank:create / bank:void). Create needs
  STAFF+, void needs MANAGER+. Double-void -> 400, unknown id -> 404,
  bad date -> 400. Mutations audited. DTOs added.

Verified against dev end-to-end: a -500 MXN charge moved a customer
balance 31082.08 -> 30582.08, and voiding it returned it to 31082.08 to
the cent; a +1234.56 bank ingreso moved net 899375.77 -> 900610.33 and
voiding returned it to 899375.77. VIEWER create/void both 403,
double-void 400. API compiles clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/api/src/bank/bank-movement.dto.ts

@@ -0,0 +1,19 @@
+import { IsBoolean, IsNumber, IsOptional, IsString, MinLength } from "class-validator";
+
+/**
+ * A new bank-register movement. `amount` is signed: positive = ingreso,
+ * negative = egreso (the module's sign convention). Single currency (MXN).
+ * Booked rows are never edited — a mistake is corrected by voiding + re-capture.
+ */
+export class CreateBankMovementDto {
+  @IsNumber() amount!: number;
+  @IsString() @MinLength(1) transactionDate!: string;
+
+  @IsOptional() @IsString() concept?: string;
+  @IsOptional() @IsString() reference?: string;
+  @IsOptional() @IsString() transactionType?: string;
+  @IsOptional() @IsBoolean() cleared?: boolean;
+  @IsOptional() @IsBoolean() transferred?: boolean;
+  @IsOptional() @IsString() notes?: string;
+  @IsOptional() @IsString() amountInWords?: string;
+}

apps/api/src/bank/bank.controller.ts

@@ -1,11 +1,25 @@
-import { Controller, Get, Query, UseGuards } from "@nestjs/common";
+import {
+  Body,
+  Controller,
+  Get,
+  Param,
+  Post,
+  Query,
+  Req,
+  UseGuards,
+} from "@nestjs/common";
+import { Request } from "express";
 import { AuthenticatedGuard } from "../auth/authenticated.guard";
+import { AbilityGuard } from "../auth/ability.guard";
+import { RequireAbility } from "../auth/require-ability.decorator";
+import { AuditService } from "../common/audit.service";
 import {
   BankCleared,
   BankDirection,
   BankService,
   BankSort,
 } from "./bank.service";
+import { CreateBankMovementDto } from "./bank-movement.dto";
 
 const DIRECTIONS: BankDirection[] = ["income", "expense", "void"];
 const CLEARED: BankCleared[] = ["cleared", "pending"];
@@ -28,10 +42,17 @@ function parseDate(v: string | undefined, endOfDay = false): Date | undefined {
   return Number.isNaN(d.getTime()) ? undefined : d;
 }
 
-@UseGuards(AuthenticatedGuard)
+@UseGuards(AuthenticatedGuard, AbilityGuard)
 @Controller("bank")
 export class BankController {
-  constructor(private readonly bank: BankService) {}
+  constructor(
+    private readonly bank: BankService,
+    private readonly audit: AuditService,
+  ) {}
+
+  private actingId(req: Request): string {
+    return (req.user as { id: string }).id;
+  }
 
   @Get("stats")
   stats() {
@@ -75,4 +96,25 @@ export class BankController {
       sort: one(SORTS, sort) ?? "date_desc",
     });
   }
+
+  // --- writes ---------------------------------------------------------------
+
+  @Post()
+  @RequireAbility("bank:create")
+  async create(@Body() dto: CreateBankMovementDto, @Req() req: Request) {
+    const row = await this.bank.createMovement(dto);
+    void this.audit.log(this.actingId(req), "bank.create", {
+      bankTransactionId: row.id,
+      amount: dto.amount,
+    });
+    return row;
+  }
+
+  @Post(":id/void")
+  @RequireAbility("bank:void")
+  async void(@Param("id") id: string, @Req() req: Request) {
+    const row = await this.bank.voidMovement(id, this.actingId(req));
+    void this.audit.log(this.actingId(req), "bank.void", { bankTransactionId: id });
+    return row;
+  }
 }

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

@@ -1,6 +1,15 @@
-import { Injectable } from "@nestjs/common";
+import { BadRequestException, Injectable, NotFoundException } from "@nestjs/common";
 import { Prisma } from "@jorgecuadros/database";
 import { PrismaService } from "../prisma/prisma.service";
+import { CreateBankMovementDto } from "./bank-movement.dto";
+
+/**
+ * App-voided rows (voidedAt set) are reversed and must leave every
+ * income/expense/net total. This is distinct from the legacy zero-amount
+ * "void" cheques, which stay as amount-0 rows. List views still show voided
+ * rows struck-through.
+ */
+const NOT_VOIDED: Prisma.BankTransactionWhereInput = { voidedAt: null };
 
 /**
  * Bank register (chequera) module — plan step 7.
@@ -160,6 +169,7 @@ export class BankService {
           notes: true,
           amountInWords: true,
           legacySourceTable: true,
+          voidedAt: true,
         },
       }),
     ]);
@@ -182,6 +192,7 @@ export class BankService {
         notes: r.notes,
         amountInWords: r.amountInWords,
         source: r.legacySourceTable,
+        voided: r.voidedAt != null,
       })),
       total,
       page: params.page,
@@ -195,17 +206,17 @@ export class BankService {
   private async totalsFor(where: Prisma.BankTransactionWhereInput) {
     const [income, expense, voided] = await Promise.all([
       this.prisma.bankTransaction.aggregate({
-        where: { AND: [where, { amount: { gt: 0 } }] },
+        where: { AND: [where, { amount: { gt: 0 } }, NOT_VOIDED] },
         _sum: { amount: true },
         _count: { _all: true },
       }),
       this.prisma.bankTransaction.aggregate({
-        where: { AND: [where, { amount: { lt: 0 } }] },
+        where: { AND: [where, { amount: { lt: 0 } }, NOT_VOIDED] },
         _sum: { amount: true },
         _count: { _all: true },
       }),
       this.prisma.bankTransaction.count({
-        where: { AND: [where, { amount: 0 }] },
+        where: { AND: [where, { amount: 0 }, NOT_VOIDED] },
       }),
     ]);
 
@@ -225,13 +236,18 @@ export class BankService {
   /** Top-line figures for the bank page header. */
   async stats() {
     const [count, bounds, pending, transferred, totals] = await Promise.all([
-      this.prisma.bankTransaction.count(),
+      this.prisma.bankTransaction.count({ where: NOT_VOIDED }),
       this.prisma.bankTransaction.aggregate({
+        where: NOT_VOIDED,
         _min: { transactionDate: true },
         _max: { transactionDate: true },
       }),
-      this.prisma.bankTransaction.count({ where: { cleared: false } }),
-      this.prisma.bankTransaction.count({ where: { transferred: true } }),
+      this.prisma.bankTransaction.count({
+        where: { AND: [{ cleared: false }, NOT_VOIDED] },
+      }),
+      this.prisma.bankTransaction.count({
+        where: { AND: [{ transferred: true }, NOT_VOIDED] },
+      }),
       this.totalsFor({}),
     ]);
 
@@ -252,6 +268,7 @@ export class BankService {
     >`
       SELECT YEAR(transactionDate) AS year, COUNT(*) AS count
       FROM bank_transactions
+      WHERE voidedAt IS NULL
       GROUP BY year
       ORDER BY year DESC
     `;
@@ -280,6 +297,7 @@ 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
       GROUP BY period
       ORDER BY period ASC
     `;
@@ -293,7 +311,7 @@ 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}
+          WHERE YEAR(transactionDate) = ${year} AND voidedAt IS NULL
           GROUP BY period
           ORDER BY period ASC
         `
@@ -346,6 +364,39 @@ export class BankService {
       opening: opening.toFixed(2),
     };
   }
+
+  // --- writes (append + void) -----------------------------------------------
+
+  async createMovement(dto: CreateBankMovementDto) {
+    const date = new Date(dto.transactionDate);
+    if (isNaN(date.getTime())) throw new BadRequestException("Fecha inválida");
+    return this.prisma.bankTransaction.create({
+      data: {
+        amount: dto.amount,
+        transactionDate: date,
+        concept: dto.concept,
+        reference: dto.reference,
+        transactionType: dto.transactionType,
+        cleared: dto.cleared ?? false,
+        transferred: dto.transferred ?? false,
+        notes: dto.notes,
+        amountInWords: dto.amountInWords,
+      },
+    });
+  }
+
+  async voidMovement(id: string, userId: string) {
+    const row = await this.prisma.bankTransaction.findUnique({
+      where: { id },
+      select: { id: true, voidedAt: true },
+    });
+    if (!row) throw new NotFoundException(`Bank transaction ${id} not found`);
+    if (row.voidedAt) throw new BadRequestException("El movimiento ya está anulado");
+    return this.prisma.bankTransaction.update({
+      where: { id },
+      data: { voidedAt: new Date(), voidedById: userId },
+    });
+  }
 }
 
 function directionOf(amount: Prisma.Decimal): BankDirection {