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/internal/infrastructure/postgres/query.sql

@@ -1,18 +1,18 @@
 -- name: ListProjects :many
-SELECT id, user_id, title, brief, status, thumbnail, updated_at
+SELECT id, user_id, title, brief, status, thumbnail, brand_kit_id, updated_at
 FROM projects
 WHERE user_id = $1
 ORDER BY updated_at DESC;
 
 -- name: ListProjectsPage :many
-SELECT id, user_id, title, brief, status, thumbnail, updated_at
+SELECT id, user_id, title, brief, status, thumbnail, brand_kit_id, updated_at
 FROM projects
 WHERE user_id = $1
 ORDER BY updated_at DESC
 LIMIT $2 OFFSET $3;
 
 -- name: GetProject :one
-SELECT id, user_id, title, brief, status, thumbnail, canvas, version, snapshot_id, last_thread_id, viewport_x, viewport_y, viewport_k, updated_at
+SELECT id, user_id, title, brief, status, thumbnail, canvas, version, snapshot_id, last_thread_id, brand_kit_id, viewport_x, viewport_y, viewport_k, updated_at
 FROM projects
 WHERE id = $1 AND user_id = $2;
 
@@ -27,8 +27,8 @@ DELETE FROM projects
 WHERE id = $1 AND user_id = $2;
 
 -- name: UpsertProject :exec
-INSERT INTO projects (id, user_id, title, brief, status, thumbnail, canvas, version, snapshot_id, last_thread_id, viewport_x, viewport_y, viewport_k, updated_at)
-VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14)
+INSERT INTO projects (id, user_id, title, brief, status, thumbnail, canvas, version, snapshot_id, last_thread_id, brand_kit_id, viewport_x, viewport_y, viewport_k, updated_at)
+VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $14, $15)
 ON CONFLICT (id) DO UPDATE SET
     user_id = EXCLUDED.user_id,
     title = EXCLUDED.title,
@@ -39,11 +39,50 @@ ON CONFLICT (id) DO UPDATE SET
     version = EXCLUDED.version,
     snapshot_id = EXCLUDED.snapshot_id,
     last_thread_id = EXCLUDED.last_thread_id,
+    brand_kit_id = EXCLUDED.brand_kit_id,
     viewport_x = EXCLUDED.viewport_x,
     viewport_y = EXCLUDED.viewport_y,
     viewport_k = EXCLUDED.viewport_k,
     updated_at = EXCLUDED.updated_at;
 
+-- name: ListBrandKits :many
+SELECT id, user_id, name, document, is_default, created_at, updated_at
+FROM brand_kits
+WHERE user_id = $1
+ORDER BY updated_at DESC, id ASC;
+
+-- name: GetBrandKit :one
+SELECT id, user_id, name, document, is_default, created_at, updated_at
+FROM brand_kits
+WHERE id = $1 AND user_id = $2;
+
+-- name: GetDefaultBrandKit :one
+SELECT id, user_id, name, document, is_default, created_at, updated_at
+FROM brand_kits
+WHERE user_id = $1 AND is_default = TRUE
+LIMIT 1;
+
+-- name: ClearDefaultBrandKits :exec
+UPDATE brand_kits
+SET is_default = FALSE
+WHERE user_id = $1 AND is_default = TRUE AND id <> $2;
+
+-- name: UpsertBrandKit :one
+INSERT INTO brand_kits (id, user_id, name, document, is_default, created_at, updated_at)
+VALUES ($1, $2, $3, $4, $5, $6, $7)
+ON CONFLICT (id) DO UPDATE SET
+    name = EXCLUDED.name,
+    document = EXCLUDED.document,
+    is_default = EXCLUDED.is_default,
+    updated_at = EXCLUDED.updated_at
+WHERE brand_kits.user_id = EXCLUDED.user_id
+RETURNING id, user_id, name, document, is_default, created_at, updated_at;
+
+-- name: DeleteBrandKit :one
+DELETE FROM brand_kits
+WHERE id = $1 AND user_id = $2
+RETURNING id;
+
 -- name: CreateCanvasSnapshot :exec
 INSERT INTO canvas_snapshots (id, project_id, user_id, version, canvas, viewport_json, nodes_json, connections_json, created_at)
 VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)