feat: implement task management module

Backend (FastAPI):
- Database migration for spaces, projects, task_statuses, tasks tables
- SQLAlchemy models with relationships
- Pydantic schemas for CRUD operations
- Spaces API: CRUD with soft delete
- Projects API: CRUD with auto-created default statuses
- Tasks API: CRUD, status change, assign, subtask support
- Permission middleware with Security Level filtering
- Subtask depth limit (max 2 levels)

Frontend (React + Vite):
- Layout component with navigation
- Spaces list page
- Projects list page
- Tasks list page with status management

Fixes:
- auth_client.py: use 'username' field for external API
- config.py: extend JWT expiry to 7 days
- auth/router.py: sync Redis session with JWT expiry

Tests: 36 passed (unit + integration)
E2E: All APIs verified with real authentication

OpenSpec: add-task-management archived

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/components/Layout.tsx

@@ -0,0 +1,131 @@
+import { ReactNode } from 'react'
+import { useNavigate, useLocation } from 'react-router-dom'
+import { useAuth } from '../contexts/AuthContext'
+
+interface LayoutProps {
+  children: ReactNode
+}
+
+export default function Layout({ children }: LayoutProps) {
+  const { user, logout } = useAuth()
+  const navigate = useNavigate()
+  const location = useLocation()
+
+  const handleLogout = async () => {
+    await logout()
+  }
+
+  const navItems = [
+    { path: '/', label: 'Dashboard' },
+    { path: '/spaces', label: 'Spaces' },
+  ]
+
+  return (
+    <div style={styles.container}>
+      <header style={styles.header}>
+        <div style={styles.headerLeft}>
+          <h1 style={styles.logo} onClick={() => navigate('/')}>
+            Project Control
+          </h1>
+          <nav style={styles.nav}>
+            {navItems.map((item) => (
+              <button
+                key={item.path}
+                onClick={() => navigate(item.path)}
+                style={{
+                  ...styles.navItem,
+                  ...(location.pathname === item.path ? styles.navItemActive : {}),
+                }}
+              >
+                {item.label}
+              </button>
+            ))}
+          </nav>
+        </div>
+        <div style={styles.headerRight}>
+          <span style={styles.userName}>{user?.name}</span>
+          {user?.is_system_admin && (
+            <span style={styles.badge}>Admin</span>
+          )}
+          <button onClick={handleLogout} style={styles.logoutButton}>
+            Logout
+          </button>
+        </div>
+      </header>
+      <main style={styles.main}>{children}</main>
+    </div>
+  )
+}
+
+const styles: { [key: string]: React.CSSProperties } = {
+  container: {
+    minHeight: '100vh',
+    backgroundColor: '#f5f5f5',
+  },
+  header: {
+    display: 'flex',
+    justifyContent: 'space-between',
+    alignItems: 'center',
+    padding: '12px 24px',
+    backgroundColor: 'white',
+    boxShadow: '0 1px 3px rgba(0, 0, 0, 0.1)',
+  },
+  headerLeft: {
+    display: 'flex',
+    alignItems: 'center',
+    gap: '24px',
+  },
+  logo: {
+    fontSize: '18px',
+    fontWeight: 600,
+    color: '#333',
+    margin: 0,
+    cursor: 'pointer',
+  },
+  nav: {
+    display: 'flex',
+    gap: '4px',
+  },
+  navItem: {
+    padding: '8px 16px',
+    backgroundColor: 'transparent',
+    border: 'none',
+    borderRadius: '4px',
+    cursor: 'pointer',
+    fontSize: '14px',
+    color: '#666',
+  },
+  navItemActive: {
+    backgroundColor: '#e3f2fd',
+    color: '#0066cc',
+    fontWeight: 500,
+  },
+  headerRight: {
+    display: 'flex',
+    alignItems: 'center',
+    gap: '12px',
+  },
+  userName: {
+    color: '#666',
+    fontSize: '14px',
+  },
+  badge: {
+    backgroundColor: '#0066cc',
+    color: 'white',
+    padding: '2px 8px',
+    borderRadius: '4px',
+    fontSize: '11px',
+    fontWeight: 500,
+  },
+  logoutButton: {
+    padding: '8px 16px',
+    backgroundColor: '#f5f5f5',
+    border: '1px solid #ddd',
+    borderRadius: '4px',
+    cursor: 'pointer',
+    fontSize: '14px',
+  },
+  main: {
+    minHeight: 'calc(100vh - 60px)',
+  },
+}