Vendor backend and frontend into the monorepo

The submodule collapse was only half applied: .gitmodules was deleted but
backend/ and frontend/ were still recorded as gitlinks, so none of their
files were tracked. Replace the gitlinks with the real trees.

Also untrack .env (it carried placeholder secrets) in favour of a tracked
.env.example, drop the committed __pycache__, and narrow the blanket *.png
ignore that would have swallowed design assets.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

frontend/src/components/Sidebar/AppSidebar.tsx

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+import { Briefcase, Home, Users } from "lucide-react"
+
+import { SidebarAppearance } from "@/components/Common/Appearance"
+import { Logo } from "@/components/Common/Logo"
+import {
+  Sidebar,
+  SidebarContent,
+  SidebarFooter,
+  SidebarHeader,
+} from "@/components/ui/sidebar"
+import useAuth from "@/hooks/useAuth"
+import { type Item, Main } from "./Main"
+import { User } from "./User"
+
+const baseItems: Item[] = [
+  { icon: Home, title: "Dashboard", path: "/" },
+  { icon: Briefcase, title: "Items", path: "/items" },
+]
+
+export function AppSidebar() {
+  const { user: currentUser } = useAuth()
+
+  const items = currentUser?.is_superuser
+    ? [...baseItems, { icon: Users, title: "Admin", path: "/admin" }]
+    : baseItems
+
+  return (
+    <Sidebar collapsible="icon">
+      <SidebarHeader className="px-4 py-6 group-data-[collapsible=icon]:px-0 group-data-[collapsible=icon]:items-center">
+        <Logo variant="responsive" />
+      </SidebarHeader>
+      <SidebarContent>
+        <Main items={items} />
+      </SidebarContent>
+      <SidebarFooter>
+        <SidebarAppearance />
+        <User user={currentUser} />
+      </SidebarFooter>
+    </Sidebar>
+  )
+}
+
+export default AppSidebar

frontend/src/components/Sidebar/Main.tsx

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+import { Link as RouterLink, useRouterState } from "@tanstack/react-router"
+import type { LucideIcon } from "lucide-react"
+
+import {
+  SidebarGroup,
+  SidebarGroupContent,
+  SidebarMenu,
+  SidebarMenuButton,
+  SidebarMenuItem,
+  useSidebar,
+} from "@/components/ui/sidebar"
+
+export type Item = {
+  icon: LucideIcon
+  title: string
+  path: string
+}
+
+interface MainProps {
+  items: Item[]
+}
+
+export function Main({ items }: MainProps) {
+  const { isMobile, setOpenMobile } = useSidebar()
+  const router = useRouterState()
+  const currentPath = router.location.pathname
+
+  const handleMenuClick = () => {
+    if (isMobile) {
+      setOpenMobile(false)
+    }
+  }
+
+  return (
+    <SidebarGroup>
+      <SidebarGroupContent>
+        <SidebarMenu>
+          {items.map((item) => {
+            const isActive = currentPath === item.path
+
+            return (
+              <SidebarMenuItem key={item.title}>
+                <SidebarMenuButton
+                  tooltip={item.title}
+                  isActive={isActive}
+                  asChild
+                >
+                  <RouterLink to={item.path} onClick={handleMenuClick}>
+                    <item.icon />
+                    <span>{item.title}</span>
+                  </RouterLink>
+                </SidebarMenuButton>
+              </SidebarMenuItem>
+            )
+          })}
+        </SidebarMenu>
+      </SidebarGroupContent>
+    </SidebarGroup>
+  )
+}

frontend/src/components/Sidebar/User.tsx

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+import { Link as RouterLink } from "@tanstack/react-router"
+import { ChevronsUpDown, LogOut, Settings } from "lucide-react"
+
+import { Avatar, AvatarFallback } from "@/components/ui/avatar"
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuLabel,
+  DropdownMenuSeparator,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu"
+import {
+  SidebarMenu,
+  SidebarMenuButton,
+  SidebarMenuItem,
+  useSidebar,
+} from "@/components/ui/sidebar"
+import useAuth from "@/hooks/useAuth"
+import { getInitials } from "@/utils"
+
+interface UserInfoProps {
+  fullName?: string
+  email?: string
+}
+
+function UserInfo({ fullName, email }: UserInfoProps) {
+  return (
+    <div className="flex items-center gap-2.5 w-full min-w-0">
+      <Avatar className="size-8">
+        <AvatarFallback className="bg-zinc-600 text-white">
+          {getInitials(fullName || "User")}
+        </AvatarFallback>
+      </Avatar>
+      <div className="flex flex-col items-start min-w-0">
+        <p className="text-sm font-medium truncate w-full">{fullName}</p>
+        <p className="text-xs text-muted-foreground truncate w-full">{email}</p>
+      </div>
+    </div>
+  )
+}
+
+export function User({ user }: { user: any }) {
+  const { logout } = useAuth()
+  const { isMobile, setOpenMobile } = useSidebar()
+
+  if (!user) return null
+
+  const handleMenuClick = () => {
+    if (isMobile) {
+      setOpenMobile(false)
+    }
+  }
+  const handleLogout = async () => {
+    logout()
+  }
+
+  return (
+    <SidebarMenu>
+      <SidebarMenuItem>
+        <DropdownMenu>
+          <DropdownMenuTrigger asChild>
+            <SidebarMenuButton
+              size="lg"
+              className="data-[state=open]:bg-sidebar-accent data-[state=open]:text-sidebar-accent-foreground"
+              data-testid="user-menu"
+            >
+              <UserInfo fullName={user?.full_name} email={user?.email} />
+              <ChevronsUpDown className="ml-auto size-4 text-muted-foreground" />
+            </SidebarMenuButton>
+          </DropdownMenuTrigger>
+          <DropdownMenuContent
+            className="w-(--radix-dropdown-menu-trigger-width) min-w-56 rounded-lg"
+            side={isMobile ? "bottom" : "right"}
+            align="end"
+            sideOffset={4}
+          >
+            <DropdownMenuLabel className="p-0 font-normal">
+              <UserInfo fullName={user?.full_name} email={user?.email} />
+            </DropdownMenuLabel>
+            <DropdownMenuSeparator />
+            <RouterLink to="/settings" onClick={handleMenuClick}>
+              <DropdownMenuItem>
+                <Settings />
+                User Settings
+              </DropdownMenuItem>
+            </RouterLink>
+            <DropdownMenuItem onClick={handleLogout}>
+              <LogOut />
+              Log Out
+            </DropdownMenuItem>
+          </DropdownMenuContent>
+        </DropdownMenu>
+      </SidebarMenuItem>
+    </SidebarMenu>
+  )
+}