Complete Phase 2: Frontend implementation with React + TypeScript

Frontend Features:
- React 18 + Vite + TypeScript + Tailwind CSS + Zustand
- JWT authentication with automatic token refresh
- Tree library with search and category filtering
- Full tree navigation (decision/action/solution nodes)
- Session management with notes and completion
- Session history with export (Markdown/Text/HTML)
- ErrorBoundary for graceful error handling

Backend Fixes:
- CORS: Added port 5174 to allowed origins
- Sessions: Fixed JSONB datetime serialization (mode='json')

Documentation:
- Updated PROGRESS.md with Phase 2 completion
- Updated 03-DEVELOPMENT-ROADMAP.md with checked items
- Added PHASE-2.5-PERSONAL-BRANCHING.md spec

Seed Data:
- Added backend/scripts/seed_data.py with Password Reset tree

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

frontend/src/components/layout/AppLayout.tsx

@@ -0,0 +1,72 @@
+import { Link, useLocation, useNavigate, Outlet } from 'react-router-dom'
+import { useAuthStore } from '@/store/authStore'
+import { cn } from '@/lib/utils'
+
+export function AppLayout() {
+  const location = useLocation()
+  const navigate = useNavigate()
+  const { user, logout } = useAuthStore()
+
+  const handleLogout = async () => {
+    await logout()
+    navigate('/login')
+  }
+
+  const navItems = [
+    { path: '/trees', label: 'Trees' },
+    { path: '/sessions', label: 'Sessions' },
+  ]
+
+  return (
+    <div className="min-h-screen bg-background">
+      {/* Header */}
+      <header className="sticky top-0 z-50 border-b border-border bg-card">
+        <div className="container mx-auto flex h-14 items-center justify-between px-4">
+          <div className="flex items-center gap-8">
+            <Link to="/trees" className="text-lg font-bold text-foreground">
+              Apoklisis
+            </Link>
+            <nav className="hidden items-center gap-1 sm:flex">
+              {navItems.map((item) => (
+                <Link
+                  key={item.path}
+                  to={item.path}
+                  className={cn(
+                    'rounded-md px-3 py-2 text-sm font-medium transition-colors',
+                    location.pathname.startsWith(item.path)
+                      ? 'bg-accent text-accent-foreground'
+                      : 'text-muted-foreground hover:bg-accent hover:text-accent-foreground'
+                  )}
+                >
+                  {item.label}
+                </Link>
+              ))}
+            </nav>
+          </div>
+
+          <div className="flex items-center gap-4">
+            <span className="hidden text-sm text-muted-foreground sm:block">
+              {user?.name || user?.email}
+            </span>
+            <button
+              onClick={handleLogout}
+              className={cn(
+                'rounded-md px-3 py-1.5 text-sm font-medium',
+                'text-muted-foreground hover:bg-accent hover:text-accent-foreground'
+              )}
+            >
+              Logout
+            </button>
+          </div>
+        </div>
+      </header>
+
+      {/* Main Content */}
+      <main>
+        <Outlet />
+      </main>
+    </div>
+  )
+}
+
+export default AppLayout