feat(server): add brand kit management and project binding

Add a brand kit domain with memory and postgres stores, a BrandKitService
for CRUD and resolution, and REST endpoints to list, upsert, and delete
brand kits. Projects can bind a brand kit whose resolved context and
reference images feed into the agent's long-term memory and design prompts.

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

server/img_infinite_canvas.api

@@ -157,13 +157,14 @@ type AccountDeviceMutationResponse {
 }
 
 type ProjectSummary {
-	Id        string `json:"id"`
-	UserId    string `json:"userId"`
-	Title     string `json:"title"`
-	Brief     string `json:"brief"`
-	Status    string `json:"status"`
-	Thumbnail string `json:"thumbnail"`
-	UpdatedAt string `json:"updatedAt"`
+	Id         string `json:"id"`
+	UserId     string `json:"userId"`
+	Title      string `json:"title"`
+	Brief      string `json:"brief"`
+	Status     string `json:"status"`
+	Thumbnail  string `json:"thumbnail"`
+	BrandKitId string `json:"brandKitId,optional"`
+	UpdatedAt  string `json:"updatedAt"`
 }
 
 type CanvasViewport {
@@ -292,6 +293,7 @@ type Project {
 	SnapshotId   string             `json:"snapshotId"`
 	Canvas       string             `json:"canvas"`
 	LastThreadId string             `json:"lastThreadId"`
+	BrandKitId   string             `json:"brandKitId,optional"`
 	Viewport     CanvasViewport     `json:"viewport"`
 	Nodes        []CanvasNode       `json:"nodes"`
 	Connections  []CanvasConnection `json:"connections"`
@@ -326,14 +328,52 @@ type QueryProjectRequest {
 }
 
 type CreateProjectRequest {
-	Title            string `json:"title,optional"`
-	Prompt           string `json:"prompt,optional"`
-	ImageModel       string `json:"imageModel,optional"`
-	ImageSize        string `json:"imageSize,optional"`
-	ImageQuality     string `json:"imageQuality,optional"`
-	ImageCount       int64  `json:"imageCount,optional"`
-	EnableWebSearch  bool   `json:"enableWebSearch,optional"`
-	AllowEmptyPrompt bool   `json:"allowEmptyPrompt,optional"`
+	Title            string  `json:"title,optional"`
+	Prompt           string  `json:"prompt,optional"`
+	BrandKitId       *string `json:"brandKitId,optional"`
+	ImageModel       string  `json:"imageModel,optional"`
+	ImageSize        string  `json:"imageSize,optional"`
+	ImageQuality     string  `json:"imageQuality,optional"`
+	ImageCount       int64   `json:"imageCount,optional"`
+	EnableWebSearch  bool    `json:"enableWebSearch,optional"`
+	AllowEmptyPrompt bool    `json:"allowEmptyPrompt,optional"`
+}
+
+type BrandKit {
+	Id        string `json:"id"`
+	Name      string `json:"name"`
+	Document  string `json:"document"`
+	IsDefault bool   `json:"isDefault"`
+	CreatedAt string `json:"createdAt"`
+	UpdatedAt string `json:"updatedAt"`
+}
+
+type BrandKitListResponse {
+	BrandKits []BrandKit `json:"brandKits"`
+}
+
+type BrandKitResponse {
+	BrandKit BrandKit `json:"brandKit"`
+}
+
+type BrandKitIdRequest {
+	Id string `path:"id"`
+}
+
+type UpsertBrandKitRequest {
+	Id        string `path:"id"`
+	Document  string `json:"document"`
+	IsDefault bool   `json:"isDefault,optional"`
+}
+
+type DeleteBrandKitResponse {
+	Id      string `json:"id"`
+	Deleted bool   `json:"deleted"`
+}
+
+type UpdateProjectBrandKitRequest {
+	Id         string `path:"id"`
+	BrandKitId string `json:"brandKitId,optional"`
 }
 
 type UpdateProjectTitleRequest {
@@ -383,6 +423,7 @@ type QueryProjectData {
 	Version        string                `json:"version"`
 	SnapshotId     *string               `json:"snapshotId"`
 	ItemId         *string               `json:"itemId"`
+	BrandKitId     string                `json:"brandKitId,optional"`
 	Permission     string                `json:"permission"`
 }
 
@@ -1008,6 +1049,15 @@ service img_infinite_canvas-api {
 	@handler logoutAccount
 	post /account/logout returns (AccountDeviceMutationResponse)
 
+	@handler listBrandKits
+	get /brand-kits returns (BrandKitListResponse)
+
+	@handler upsertBrandKit
+	put /brand-kits/:id (UpsertBrandKitRequest) returns (BrandKitResponse)
+
+	@handler deleteBrandKit
+	delete /brand-kits/:id (BrandKitIdRequest) returns (DeleteBrandKitResponse)
+
 	@handler listProjects
 	get /projects (ProjectListRequest) returns (ProjectListResponse)
 
@@ -1041,6 +1091,9 @@ service img_infinite_canvas-api {
 	@handler updateProjectTitle
 	patch /projects/:id/title (UpdateProjectTitleRequest) returns (ProjectResponse)
 
+	@handler updateProjectBrandKit
+	patch /projects/:id/brand-kit (UpdateProjectBrandKitRequest) returns (ProjectResponse)
+
 	@handler getProject
 	get /projects/:id (ProjectIdRequest) returns (ProjectResponse)