test: add initial unit integration and e2e coverage

Adds the initial testing baseline for the project:

   Unit coverage:
   - Zod schemas for items, assignments, movements, categories, auth, recipients, users, and assets
   - password hashing and verification helpers
   - auth role helper functions

   Integration coverage with PostgreSQL Testcontainers:
   - item use-cases: create, duplicate names, delete constraints
   - assignment use-cases: create, insufficient stock, return, double return
   - asset use-cases: available/assigned creation and lifecycle transitions
   - user use-cases: create/update, uniqueness, admin safeguards, password reset
   - category use-cases: create/update/delete constraints
   - recipient use-cases: create/update and uniqueness constraints

   E2E smoke coverage with Playwright:
   - unauthenticated redirect to login
   - seeded admin login
   - dashboard load
   - admin users page
   - inventory items page
   - assignments page

   Also configures:
   - Vitest
   - Playwright
   - PostgreSQL Testcontainers helpers
   - deterministic E2E admin bootstrap
   - test artifact ignores

   Validation:
   - bun run test: 9 files / 37 tests passed
   - bun run test:e2e: 3 passed
   - bunx tsc --noEmit: passed
   - bunx prisma validate: passed

tests/integration/helpers/test-db.ts

@@ -0,0 +1,72 @@
+import { execFileSync } from "node:child_process"
+import {
+  PostgreSqlContainer,
+  type StartedPostgreSqlContainer,
+} from "@testcontainers/postgresql"
+import type { PrismaClient } from "@/generated/prisma/client"
+
+type TestDatabaseState = {
+  container?: StartedPostgreSqlContainer
+  databaseUrl?: string
+}
+
+const state: TestDatabaseState = {}
+
+const TABLES_TO_TRUNCATE = [
+  "Movement",
+  "Assignment",
+  "Asset",
+  "Item",
+  "Category",
+  "Recipient",
+  "User",
+]
+
+export async function startIntegrationTestDatabase() {
+  if (state.container && state.databaseUrl) {
+    return state.databaseUrl
+  }
+
+  const container = await new PostgreSqlContainer("postgres:18-alpine")
+    .withDatabase("stock_manager_test")
+    .withUsername("test")
+    .withPassword("test")
+    .start()
+
+  const databaseUrl = container.getConnectionUri()
+
+  state.container = container
+  state.databaseUrl = databaseUrl
+
+  process.env.DATABASE_URL = databaseUrl
+  process.env.AUTH_SECRET = process.env.AUTH_SECRET || "test-auth-secret"
+
+  try {
+    execFileSync("bunx", ["prisma", "migrate", "deploy"], {
+      env: {
+        ...process.env,
+        DATABASE_URL: databaseUrl,
+      },
+      stdio: "inherit",
+    })
+  } catch (error) {
+    await stopIntegrationTestDatabase()
+    throw error
+  }
+
+  return databaseUrl
+}
+
+export async function resetIntegrationTestDatabase(prisma: PrismaClient) {
+  const quotedTables = TABLES_TO_TRUNCATE.map((table) => `"${table}"`).join(
+    ", ",
+  )
+
+  await prisma.$executeRawUnsafe(`TRUNCATE TABLE ${quotedTables} CASCADE`)
+}
+
+export async function stopIntegrationTestDatabase() {
+  await state.container?.stop()
+  state.container = undefined
+  state.databaseUrl = undefined
+}