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/unit/lib/security.test.ts

@@ -0,0 +1,16 @@
+import { describe, expect, it } from "vitest"
+import { getPasswordHash, verifyPassword } from "@/lib/security"
+
+describe("security helpers", () => {
+  it("hashes passwords and verifies the original plain password", async () => {
+    const hash = await getPasswordHash("secure-password")
+
+    expect(hash).not.toBe("secure-password")
+    await expect(verifyPassword("secure-password", hash)).resolves.toBe(true)
+    await expect(verifyPassword("wrong-password", hash)).resolves.toBe(false)
+  })
+
+  it("rejects empty passwords when hashing", async () => {
+    await expect(getPasswordHash("")).rejects.toThrow("Password is required")
+  })
+})