feat(02-02): JournalEntry models + JournalEntryService

- Add JournalEntryStatus and JournalEntrySource enums to Prisma schema
- Add JournalEntry model with maker-checker fields, self-referential reversal relation, and audit timestamps
- Add JournalEntryLine model with debit/credit Decimal(15,2) fields
- Update Account model with journalEntryLines back-relation
- Update User model with createdJournalEntries and approvedJournalEntries back-relations
- Run migration: 20260304150817_add_journal_entry_models
- Add journalEntry and journalEntryLine to TENANT_SCOPED_MODELS in prisma-tenant.ts
- Create JournalEntryService with createEntry, approveEntry, reverseEntry, getAccountBalance, getTrialBalance
- Enforce debit=credit balance using integer cents comparison (avoids float issues)
- SYSTEM source entries auto-posted; MANUAL entries start as DRAFT for maker-checker

prisma/migrations/20260304150817_add_journal_entry_models/migration.sql

@@ -0,0 +1,79 @@
+-- CreateEnum
+CREATE TYPE "JournalEntryStatus" AS ENUM ('DRAFT', 'PENDING_APPROVAL', 'APPROVED', 'POSTED', 'REVERSED');
+
+-- CreateEnum
+CREATE TYPE "JournalEntrySource" AS ENUM ('SYSTEM', 'MANUAL');
+
+-- CreateTable
+CREATE TABLE "JournalEntry" (
+    "id" TEXT NOT NULL,
+    "tenantId" TEXT NOT NULL,
+    "entryNumber" TEXT NOT NULL,
+    "date" TIMESTAMP(3) NOT NULL,
+    "description" TEXT NOT NULL,
+    "source" "JournalEntrySource" NOT NULL,
+    "status" "JournalEntryStatus" NOT NULL DEFAULT 'DRAFT',
+    "referenceType" TEXT,
+    "referenceId" TEXT,
+    "reversesEntryId" TEXT,
+    "createdById" TEXT NOT NULL,
+    "approvedById" TEXT,
+    "approvedAt" TIMESTAMP(3),
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "JournalEntry_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateTable
+CREATE TABLE "JournalEntryLine" (
+    "id" TEXT NOT NULL,
+    "tenantId" TEXT NOT NULL,
+    "journalEntryId" TEXT NOT NULL,
+    "accountId" TEXT NOT NULL,
+    "debit" DECIMAL(15,2) NOT NULL DEFAULT 0,
+    "credit" DECIMAL(15,2) NOT NULL DEFAULT 0,
+    "description" TEXT,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "JournalEntryLine_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "JournalEntry_reversesEntryId_key" ON "JournalEntry"("reversesEntryId");
+
+-- CreateIndex
+CREATE INDEX "JournalEntry_tenantId_idx" ON "JournalEntry"("tenantId");
+
+-- CreateIndex
+CREATE INDEX "JournalEntry_tenantId_date_idx" ON "JournalEntry"("tenantId", "date");
+
+-- CreateIndex
+CREATE INDEX "JournalEntry_referenceType_referenceId_idx" ON "JournalEntry"("referenceType", "referenceId");
+
+-- CreateIndex
+CREATE UNIQUE INDEX "JournalEntry_tenantId_entryNumber_key" ON "JournalEntry"("tenantId", "entryNumber");
+
+-- CreateIndex
+CREATE INDEX "JournalEntryLine_tenantId_idx" ON "JournalEntryLine"("tenantId");
+
+-- CreateIndex
+CREATE INDEX "JournalEntryLine_accountId_idx" ON "JournalEntryLine"("accountId");
+
+-- CreateIndex
+CREATE INDEX "JournalEntryLine_journalEntryId_idx" ON "JournalEntryLine"("journalEntryId");
+
+-- AddForeignKey
+ALTER TABLE "JournalEntry" ADD CONSTRAINT "JournalEntry_reversesEntryId_fkey" FOREIGN KEY ("reversesEntryId") REFERENCES "JournalEntry"("id") ON DELETE SET NULL ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "JournalEntry" ADD CONSTRAINT "JournalEntry_createdById_fkey" FOREIGN KEY ("createdById") REFERENCES "User"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "JournalEntry" ADD CONSTRAINT "JournalEntry_approvedById_fkey" FOREIGN KEY ("approvedById") REFERENCES "User"("id") ON DELETE SET NULL ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "JournalEntryLine" ADD CONSTRAINT "JournalEntryLine_journalEntryId_fkey" FOREIGN KEY ("journalEntryId") REFERENCES "JournalEntry"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "JournalEntryLine" ADD CONSTRAINT "JournalEntryLine_accountId_fkey" FOREIGN KEY ("accountId") REFERENCES "Account"("id") ON DELETE RESTRICT ON UPDATE CASCADE;