feat(phase-9): implement MVP polishing and closure

T-032: User management admin panel - backend users router with CRUD, frontend UsersPage with modals

T-033: Audit log viewer - backend audit router with filters/pagination, frontend AuditLogPage

T-034: Global error handling - ErrorBoundary, LoadingSpinner, ErrorMessage, Toast components

T-035: Backend tests - pytest setup with SQLite, tests for health/auth/techniques/tests

T-036: Documentation - Updated README with testing section, created docs/API.md

backend/app/schemas/user.py

@@ -0,0 +1,45 @@
+"""Pydantic schemas for User management endpoints."""
+
+import uuid
+from datetime import datetime
+
+from pydantic import BaseModel, ConfigDict, EmailStr
+
+
+# ── Create ──────────────────────────────────────────────────────────
+
+class UserCreate(BaseModel):
+    """Payload for creating a new user."""
+
+    username: str
+    email: str | None = None
+    password: str
+    role: str = "viewer"
+
+
+# ── Update ──────────────────────────────────────────────────────────
+
+class UserUpdate(BaseModel):
+    """Payload for partially updating an existing user.
+    Every field is optional so callers send only what changed."""
+
+    email: str | None = None
+    role: str | None = None
+    is_active: bool | None = None
+    password: str | None = None
+
+
+# ── Read (full) ─────────────────────────────────────────────────────
+
+class UserOut(BaseModel):
+    """Complete representation returned by the API."""
+
+    id: uuid.UUID
+    username: str
+    email: str | None = None
+    role: str
+    is_active: bool
+    created_at: datetime | None = None
+    last_login: datetime | None = None
+
+    model_config = ConfigDict(from_attributes=True)