feat(frontend): add brand kit management UI and project binding

Add a brand kit domain model, repository, and dedicated page/route for
managing brand kits, plus a BrandKitSelector used on the home page and
canvas workspace. Home project creation and the workspace can attach a
brand kit to a project, with new i18n strings and a side-nav entry.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/ui/pages/BrandKitRoutePage/index.tsx

@@ -0,0 +1,89 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import type { BrandKit } from "@/domain/brandKit";
+import { openBrandKit, openHome, openProject, openProjects } from "@/application/route";
+import { brandKitStorageScope } from "@/infrastructure/brandKitRepository";
+import { designGateway } from "@/infrastructure/designGateway";
+import { useI18n } from "@/i18n/i18n";
+import { useAuth } from "@/ui/auth/AuthProvider";
+import { useGlobalToast } from "@/ui/components/CanvasToast";
+import { useUserMessage } from "@/ui/hooks/useUserMessage";
+import { BrandKitPage } from "@/ui/pages/BrandKitPage";
+import { SideNav, TopBar } from "@/ui/pages/HomeShell";
+
+export function BrandKitRoutePage() {
+  const { t } = useI18n();
+  const { isAuthenticated, openLogin, requireAuth, user } = useAuth();
+  const { showError } = useGlobalToast();
+  const toUserMessageText = useUserMessage();
+  const [credits, setCredits] = useState(30);
+  const [creatingProject, setCreatingProject] = useState(false);
+  const storageScope = brandKitStorageScope(user?.id);
+
+  useEffect(() => {
+    if (!isAuthenticated) openLogin();
+  }, [isAuthenticated, openLogin]);
+
+  useEffect(() => {
+    if (!isAuthenticated) {
+      setCredits(30);
+      return;
+    }
+    designGateway
+      .dashboard()
+      .then((dashboard) => setCredits(dashboard.credits))
+      .catch(() => undefined);
+  }, [isAuthenticated]);
+
+  const createEmptyProject = () => {
+    requireAuth(async () => {
+      setCreatingProject(true);
+      try {
+        const { project } = await designGateway.createProjectAsync("", undefined, {
+          imageModel: "gpt-image-2",
+          allowEmptyPrompt: true
+        });
+        openProject(project.id);
+      } catch (error) {
+        showError(toUserMessageText(error, "createError"));
+      } finally {
+        setCreatingProject(false);
+      }
+    });
+  };
+
+  const createProjectFromKit = (kit: BrandKit) => {
+    requireAuth(async () => {
+      setCreatingProject(true);
+      try {
+        const projectPrompt = t("brandKitProjectInstruction");
+        const projectTitle = t("brandKitProjectTitle", { name: kit.brandName.trim() || kit.name });
+        const { project } = await designGateway.createProjectAsync(projectPrompt, projectTitle, {
+          imageModel: "gpt-image-2",
+          brandKitId: kit.id
+        });
+        openProject(project.id);
+      } catch (error) {
+        showError(toUserMessageText(error, "createError"));
+      } finally {
+        setCreatingProject(false);
+      }
+    });
+  };
+
+  return (
+    <div className={`home-shell brand-kit-route-shell ${isAuthenticated ? "" : "is-auth-locked"}`}>
+      <TopBar credits={credits} onHome={openHome} />
+      <SideNav
+        active="brandKit"
+        onCreate={createEmptyProject}
+        onHome={openHome}
+        onProjects={openProjects}
+        onBrandKit={openBrandKit}
+        onInspiration={openHome}
+      />
+      <BrandKitPage storageScope={storageScope} creatingProject={creatingProject} onCreateProject={createProjectFromKit} />
+    </div>
+  );
+}

frontend/src/ui/pages/CanvasWorkspace/index.tsx

@@ -2,16 +2,19 @@
 
 import { ArrowDown, BookOpen, ChevronDown, Circle, Folder, Frame, Globe2, Image as ImageIcon, Layers, Lock, LogOut, Map as MapIcon, Loader2, MessageCircle, MessageSquarePlus, PanelRightClose, PenLine, Search, Trash2, Type, User, Zap } from "lucide-react";
 import { useCallback, useEffect, useMemo, useRef, useState, type CSSProperties } from "react";
-import { openHome } from "@/application/route";
+import { openBrandKit, openHome } from "@/application/route";
 import { ContextMenu, ContextMenuTrigger } from "@/components/ui/context-menu";
 import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
+import type { BrandKit } from "@/domain/brandKit";
 import type { AgentContent, AgentMessage, AgentThreadSummary, CanvasNode, CanvasViewport, ExtractedTextLayer, ExtractNodeTextResponse, MockupModel, MockupModelMap, MockupPlacement, MockupSurface, NodeActionRequest, Project, ShareAccess } from "@/domain/design";
 import { useI18n, type Locale } from "@/i18n/i18n";
+import { brandKitRepository, brandKitStorageScope } from "@/infrastructure/brandKitRepository";
 import { designGateway } from "@/infrastructure/designGateway";
 import { httpStatusOf } from "@/infrastructure/userMessages";
 import { useAuth } from "@/ui/auth/AuthProvider";
 import { AccountManagementDialog } from "@/ui/components/AccountManagementDialog";
 import { ArtboardPreview } from "@/ui/components/ArtboardPreview";
+import { BrandKitSelector } from "@/ui/components/BrandKitSelector";
 import { CanvasAnnotationPreview } from "@/ui/components/CanvasAnnotationPreview";
 import { CanvasAnnotations } from "@/ui/components/CanvasAnnotations";
 import { CanvasAgentComposer, composerImageSize, defaultComposerImageSettings, type ComposerImageSettings, type ComposerMode } from "@/ui/components/CanvasAgentComposer";
@@ -542,10 +545,11 @@ const ownerWorkspaceAccess: ShareAccess = {
 
 export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess }: { projectId: string; shareAccess?: ShareAccess }) {
   const { t, locale } = useI18n();
-  const { isAuthenticated } = useAuth();
+  const { isAuthenticated, user } = useAuth();
   const canEdit = shareAccess.capabilities.canEdit;
   const canViewChat = shareAccess.capabilities.canViewChat;
   const canManageSharing = shareAccess.capabilities.canManage;
+  const canManageBrandKit = shareAccess.isOwner;
   const toUserMessageText = useUserMessage();
   const { showToast } = useGlobalToast();
   const showGenerationError = useCallback((message: string) => showToast(message, "error"), [showToast]);
@@ -585,6 +589,9 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
   const [composerMode, setComposerMode] = useState<ComposerMode>("agent");
   const [useAgentWebSearch, setUseAgentWebSearch] = useState(false);
   const [selectedCanvasModelId, setSelectedCanvasModelId] = useState("gpt-image-2-auto");
+  const [brandKits, setBrandKits] = useState<BrandKit[]>([]);
+  const [brandKitsLoading, setBrandKitsLoading] = useState(false);
+  const [brandKitUpdating, setBrandKitUpdating] = useState(false);
   const [composerImageSettings, setComposerImageSettings] = useState<ComposerImageSettings>(defaultComposerImageSettings);
   const [canvasStageSize, setCanvasStageSize] = useState({ width: 1100, height: 760 });
   const [mode, setMode] = useState<"select" | "pan">("select");
@@ -696,6 +703,32 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
       .catch(() => undefined);
   }, [isAuthenticated]);
 
+  useEffect(() => {
+    let active = true;
+    if (!isAuthenticated || !canManageBrandKit) {
+      setBrandKits([]);
+      setBrandKitsLoading(false);
+      return;
+    }
+    setBrandKitsLoading(true);
+    brandKitRepository
+      .list(brandKitStorageScope(user?.id))
+      .then((kits) => {
+        if (active) setBrandKits(kits);
+      })
+      .catch(() => {
+        if (!active) return;
+        setBrandKits([]);
+        showToast(t("brandKitLoadError"), "error");
+      })
+      .finally(() => {
+        if (active) setBrandKitsLoading(false);
+      });
+    return () => {
+      active = false;
+    };
+  }, [canManageBrandKit, isAuthenticated, showToast, t, user?.id]);
+
   useEffect(() => {
     if (!canViewChat) {
       setAssistantPanelOpen(false);
@@ -724,6 +757,25 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
     setEditingTextNodeId(null);
   }, [applyProjectDocument, nodesRef]);
 
+  const selectProjectBrandKit = useCallback(
+    async (brandKitId: string | null) => {
+      const currentProject = projectRef.current;
+      if (!currentProject || !canManageBrandKit) return;
+      setBrandKitUpdating(true);
+      try {
+        const { project: updatedProject } = await designGateway.updateProjectBrandKit(currentProject.id, brandKitId ?? "");
+        projectRef.current = updatedProject;
+        setProject(updatedProject);
+        showToast(t(brandKitId ? "brandKitApplied" : "brandKitCleared"), "success");
+      } catch {
+        showToast(t("brandKitBindingError"), "error");
+      } finally {
+        setBrandKitUpdating(false);
+      }
+    },
+    [canManageBrandKit, projectRef, setProject, showToast, t]
+  );
+
   const appendThinkingMessage = useCallback((message: AgentMessage) => {
     if (isImageGeneratorThreadMessage(message, imageGeneratorThreadIdsRef.current)) return;
     if (message.type === "text_extraction_result" || message.name === "text_extraction") return;
@@ -3473,6 +3525,16 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
               onBackHome={openHome}
               onRename={updateProjectTitle}
             />
+            {canManageBrandKit && (
+              <BrandKitSelector
+                kits={brandKits}
+                selectedId={project.brandKitId ?? null}
+                loading={brandKitsLoading || brandKitUpdating}
+                disabled={!canEdit || brandKitUpdating || anyGenerating}
+                onSelect={selectProjectBrandKit}
+                onCreate={openBrandKit}
+              />
+            )}
           </div>
           {canViewChat ? (
             assistantPanelOpen ? (

frontend/src/ui/pages/HomePage/index.tsx

@@ -2,16 +2,19 @@
 
 import { Check, ChevronDown, Eye, Frame, Globe2, Heart, Image as ImageIcon, LayoutDashboard, Loader2, Paperclip, Palette, Plus, Search, Send, ShoppingBag, Sparkles, Wand2, X } from "lucide-react";
 import { useEffect, useMemo, useRef, useState, type CSSProperties } from "react";
-import { openHome, openProject, openProjects } from "@/application/route";
+import { openBrandKit, openHome, openProject, openProjects } from "@/application/route";
 import { Button } from "@/components/ui/button";
 import { Popover, PopoverContent, PopoverTrigger } from "@/components/ui/popover";
 import { ScrollArea } from "@/components/ui/scroll-area";
 import { Switch } from "@/components/ui/switch";
 import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
+import type { BrandKit } from "@/domain/brandKit";
 import type { Dashboard, ProjectSummary } from "@/domain/design";
 import { useI18n, type Locale } from "@/i18n/i18n";
+import { brandKitRepository, brandKitStorageScope } from "@/infrastructure/brandKitRepository";
 import { designGateway } from "@/infrastructure/designGateway";
 import { useAuth } from "@/ui/auth/AuthProvider";
+import { BrandKitSelector } from "@/ui/components/BrandKitSelector";
 import { useGlobalToast } from "@/ui/components/CanvasToast";
 import { DeleteProjectDialog } from "@/ui/components/DeleteProjectDialog";
 import { ProjectCard } from "@/ui/components/ProjectCard";
@@ -611,7 +614,7 @@ export function HomePage() {
   const { t, locale } = useI18n();
   const toUserMessageText = useUserMessage();
   const { showError } = useGlobalToast();
-  const { isAuthenticated, requireAuth } = useAuth();
+  const { isAuthenticated, requireAuth, user } = useAuth();
   const heroRef = useRef<HTMLElement | null>(null);
   const projectsRef = useRef<HTMLElement | null>(null);
   const inspirationRef = useRef<HTMLElement | null>(null);
@@ -629,6 +632,9 @@ export function HomePage() {
   const [deletingProjectId, setDeletingProjectId] = useState<string | null>(null);
   const [useWebReference, setUseWebReference] = useState(false);
   const [modelPickerOpen, setModelPickerOpen] = useState(false);
+  const [brandKits, setBrandKits] = useState<BrandKit[]>([]);
+  const [selectedBrandKitId, setSelectedBrandKitId] = useState<string | null>(null);
+  const [brandKitSelectionLoaded, setBrandKitSelectionLoaded] = useState(false);
   const [activeModelTab, setActiveModelTab] = useState<HomeModelTab>("image");
   const [selectedModelId, setSelectedModelId] = useState("gpt-image-2-auto");
   const [loading, setLoading] = useState(false);
@@ -644,6 +650,36 @@ export function HomePage() {
       .catch((err: unknown) => showError(toUserMessageText(err, "createError")));
   }, [isAuthenticated, showError, toUserMessageText]);
 
+  useEffect(() => {
+    let active = true;
+    if (!isAuthenticated) {
+      setBrandKits([]);
+      setSelectedBrandKitId(null);
+      setBrandKitSelectionLoaded(false);
+      return;
+    }
+    setBrandKitSelectionLoaded(false);
+    brandKitRepository
+      .list(brandKitStorageScope(user?.id))
+      .then((kits) => {
+        if (!active) return;
+        setBrandKits(kits);
+        setSelectedBrandKitId((current) => (current && kits.some((kit) => kit.id === current) ? current : kits.find((kit) => kit.applyToNewProjects)?.id ?? null));
+      })
+      .catch((err: unknown) => {
+        if (!active) return;
+        setBrandKits([]);
+        setSelectedBrandKitId(null);
+        showError(toUserMessageText(err, "createError"));
+      })
+      .finally(() => {
+        if (active) setBrandKitSelectionLoaded(true);
+      });
+    return () => {
+      active = false;
+    };
+  }, [isAuthenticated, showError, toUserMessageText, user?.id]);
+
   useEffect(() => {
     referenceImagesRef.current = referenceImages;
   }, [referenceImages]);
@@ -653,6 +689,7 @@ export function HomePage() {
   const promptModes = useMemo(() => getPromptModes(locale), [locale]);
   const imageModels = useMemo(() => getImageModels(locale), [locale]);
   const selectedModel = imageModels.find((model) => model.id === selectedModelId) ?? imageModels[0];
+  const selectedBrandKit = brandKits.find((kit) => kit.id === selectedBrandKitId) ?? null;
   const inspirationCategories = useMemo(() => getInspirationCategories(locale), [locale]);
   const inspirationCatalog = useMemo(() => getInspirationCatalog(locale), [locale]);
   const promptPlaceholder = useHomePromptPlaceholder(locale);
@@ -700,10 +737,12 @@ export function HomePage() {
     if (!options.allowEmptyPrompt && !hasPromptText(nextPrompt ?? prompt)) return;
     setLoading(true);
     try {
+      const submissionPrompt = composeHomePrompt(getSubmissionPrompt(nextPrompt), useWebReference, selectedModel, t);
       const { project } = await designGateway.createProjectAsync(
-        composeHomePrompt(getSubmissionPrompt(nextPrompt), useWebReference, selectedModel, t),
+        submissionPrompt,
         undefined,
         {
+          brandKitId: brandKitSelectionLoaded ? selectedBrandKitId ?? "" : undefined,
           imageModel: toImageApiModel(selectedModel.id),
           enableWebSearch: useWebReference,
           allowEmptyPrompt: options.allowEmptyPrompt
@@ -799,6 +838,7 @@ export function HomePage() {
         onCreate={() => createProject("", { allowEmptyPrompt: true })}
         onHome={() => scrollTo(heroRef.current)}
         onProjects={openProjects}
+        onBrandKit={openBrandKit}
         onInspiration={() => scrollTo(inspirationRef.current)}
       />
 
@@ -840,8 +880,23 @@ export function HomePage() {
                   <Sparkles size={13} />
                   {selectedModel.label}
                 </span>
+                {selectedBrandKit && (
+                  <span>
+                    <Palette size={13} />
+                    {selectedBrandKit.name}
+                  </span>
+                )}
               </div>
               <div className="prompt-spacer" />
+              <BrandKitSelector
+                kits={brandKits}
+                selectedId={selectedBrandKitId}
+                loading={isAuthenticated && !brandKitSelectionLoaded}
+                disabled={loading}
+                mode="icon"
+                onSelect={setSelectedBrandKitId}
+                onCreate={openBrandKit}
+              />
               <button
                 className={`icon-button bordered ${useWebReference ? "active" : ""}`}
                 aria-label={t("webReference")}

frontend/src/ui/pages/HomeShell/index.css

@@ -324,6 +324,37 @@
   }
 
   .side-nav {
+    top: auto;
+    bottom: 12px;
+    left: 50%;
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    transform: translateX(-50%);
+  }
+
+  .side-nav nav {
+    width: auto;
+    height: 52px;
+    display: flex;
+    gap: 4px;
+    padding: 4px;
+    border-color: rgba(224, 227, 232, 0.82);
+    background: rgba(255, 255, 255, 0.92);
+    box-shadow: 0 14px 34px rgba(17, 24, 39, 0.14);
+  }
+
+  .side-nav nav button {
+    width: 42px;
+    height: 42px;
+  }
+
+  .side-nav .create-fab {
+    width: 52px !important;
+    height: 52px !important;
+  }
+
+  .side-nav .settings-fab {
     display: none;
   }
 }
@@ -337,4 +368,8 @@
   .account-pill {
     display: none;
   }
+
+  .side-nav .side-nav-secondary {
+    display: none;
+  }
 }

frontend/src/ui/pages/HomeShell/index.tsx

@@ -165,12 +165,14 @@ export function SideNav({
   onCreate,
   onHome,
   onProjects,
+  onBrandKit,
   onInspiration
 }: {
-  active?: "home" | "projects";
+  active?: "home" | "projects" | "brandKit";
   onCreate: () => void;
   onHome: () => void;
   onProjects: () => void;
+  onBrandKit: () => void;
   onInspiration: () => void;
 }) {
   const { t } = useI18n();
@@ -187,10 +189,13 @@ export function SideNav({
         <button className={active === "projects" ? "active" : ""} aria-label={t("projects")} onClick={onProjects}>
           <Folder size={22} />
         </button>
-        <button aria-label={t("members")} onClick={onInspiration}>
+        <button className={active === "brandKit" ? "active" : ""} aria-label={t("brandKit")} title={t("brandKit")} onClick={onBrandKit}>
+          <BrandKitNavIcon />
+        </button>
+        <button className="side-nav-secondary" aria-label={t("members")} onClick={onInspiration}>
           <User size={22} />
         </button>
-        <button aria-label={t("info")} onClick={onInspiration}>
+        <button className="side-nav-secondary" aria-label={t("info")} onClick={onInspiration}>
           <Info size={22} />
         </button>
       </nav>
@@ -201,6 +206,14 @@ export function SideNav({
   );
 }
 
+function BrandKitNavIcon() {
+  return (
+    <svg viewBox="0 0 24 24" width="22" height="22" fill="currentColor" aria-hidden="true">
+      <path d="M12 2C17.5222 2 22 5.97778 22 10.8889C22 13.9556 19.5111 16.4444 16.4444 16.4444H14.4778C13.5556 16.4444 12.8111 17.1889 12.8111 18.1111C12.8111 18.5333 12.9778 18.9222 13.2333 19.2111C13.5 19.5111 13.6667 19.9 13.6667 20.3333C13.6667 21.2556 12.9 22 12 22C6.47778 22 2 17.5222 2 12C2 6.47778 6.47778 2 12 2ZM10.8111 18.1111C10.8111 16.0843 12.451 14.4444 14.4778 14.4444H16.4444C18.4065 14.4444 20 12.851 20 10.8889C20 7.1392 16.4677 4 12 4C7.58235 4 4 7.58235 4 12C4 16.19 7.2226 19.6285 11.324 19.9718C10.9948 19.4168 10.8111 18.7761 10.8111 18.1111ZM7.5 12C6.67157 12 6 11.3284 6 10.5C6 9.67157 6.67157 9 7.5 9C8.32843 9 9 9.67157 9 10.5C9 11.3284 8.32843 12 7.5 12ZM16.5 12C15.6716 12 15 11.3284 15 10.5C15 9.67157 15.6716 9 16.5 9C17.3284 9 18 9.67157 18 10.5C18 11.3284 17.3284 12 16.5 12ZM12 9C11.1716 9 10.5 8.32843 10.5 7.5C10.5 6.67157 11.1716 6 12 6C12.8284 6 13.5 6.67157 13.5 7.5C13.5 8.32843 12.8284 9 12 9Z" />
+    </svg>
+  );
+}
+
 export function SectionHeader({ title, action, onAction }: { title: string; action?: string; onAction?: () => void }) {
   return (
     <div className="section-header">

frontend/src/ui/pages/ProjectsRoutePage/index.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { useEffect, useState } from "react";
-import { openHome, openProject, openProjects } from "@/application/route";
+import { openBrandKit, openHome, openProject, openProjects } from "@/application/route";
 import { designGateway } from "@/infrastructure/designGateway";
 import { useAuth } from "@/ui/auth/AuthProvider";
 import { useGlobalToast } from "@/ui/components/CanvasToast";
@@ -64,6 +64,7 @@ export function ProjectsRoutePage() {
           }
           openLogin();
         }}
+        onBrandKit={openBrandKit}
         onInspiration={openHome}
       />
       <ProjectsPage locked={!isAuthenticated} creating={creating} onCreateProject={createProject} />