refactor(brands): migrate brand-loader to StorageAdapter

app/api/brands/[slug]/logos/[id]/route.ts

@@ -1,11 +1,11 @@
 import { NextResponse } from "next/server"
-import fs from "node:fs/promises"
 import { loadBrandProfile } from "@/lib/cast/server/brand-loader"
 import {
   BrandNotFoundError,
   BrandIncompleteError,
   BrandInvalidError,
 } from "@/lib/cast/errors"
+import { getStorageAdapter } from "@/lib/cast/server/storage-adapter"
 
 export const runtime = "nodejs"
 
@@ -50,11 +50,12 @@ export async function GET(
     )
   }
 
-  // TODO(symlink-hardening): variant.path was safeJoin-validated by the loader;
-  // re-validate with realpath when production hardening lands.
+  // variant.path is a container-relative key validated by the loader,
+  // e.g. "brands/brisa/logos/droplet-on-dark.png".
+  const storage = await getStorageAdapter()
   let buf: Buffer
   try {
-    buf = await fs.readFile(variant.path)
+    buf = await storage.readFile("inputs", variant.path)
   } catch (err) {
     const code = (err as NodeJS.ErrnoException).code
     if (code === "ENOENT" || code === "EACCES" || code === "EPERM") {

app/api/generate/route.ts

@@ -60,7 +60,7 @@ import {
   writeBriefSnapshot,
   writeReport,
 } from "@/lib/cast/server/storage"
-import fs from "node:fs/promises"
+import { getStorageAdapter } from "@/lib/cast/server/storage-adapter"
 import {
   emitAssetResolved,
   emitComplete,
@@ -276,12 +276,12 @@ export async function runPipeline(args: RunPipelineArgs): Promise<Manifest> {
       let baseImageGenerationError: { stage: ErrorStage; message: string } | undefined
       if (resolved.source === "local" || resolved.source === "products") {
         try {
-          // "local" → repo-relative path via readAsset; "products" → absolute
-          // path resolved by brand-loader, read directly via fs.
+          // "local" → repo-relative path via readAsset; "products" → container-relative
+          // key via readBrandAsset.
           localBaseImage =
             resolved.source === "local"
               ? await readAsset(resolved.file)
-              : await readFile(resolved.file)
+              : await readBrandAsset(resolved.file)
         } catch (err) {
           const message = errMessage(err)
           for (const ratio of brief.ratios) {
@@ -524,11 +524,10 @@ function errMessage(err: unknown): string {
 }
 
 /**
- * Read a file from an absolute path (used for brand-can variants whose paths
- * are already absolute, resolved by brand-loader). Kept separate from
- * `readAsset` which takes repo-relative inputs/-rooted paths.
+ * Read a brand asset file via StorageAdapter using a container-relative key
+ * (e.g. `brands/brisa/products/can-citrus.png`).
  */
-async function readFile(absPath: string): Promise<Buffer> {
-  return fs.readFile(absPath)
+async function readBrandAsset(key: string): Promise<Buffer> {
+  return (await getStorageAdapter()).readFile("inputs", key)
 }
 

lib/cast/schemas.ts

@@ -239,11 +239,11 @@ export type BrandProfile = {
     theme?: "light" | "dark"
   }[]
   defaultLogoId: string
-  /** Absolute path to the brand's display font. `font.ttf` or `font.otf`. */
+  /** Container-relative key to the brand's display font, e.g. `brands/acme/font.otf`. */
   fontPath: string
   /**
    * Can/product PNG variants from products.json.
-   * `file` is an absolute path (resolved by brand-loader).
+   * `file` is a container-relative key (e.g. `brands/acme/products/can.png`).
    * Empty array when products.json is absent (e.g. Volt).
    */
   canVariants: Array<{
@@ -255,7 +255,7 @@ export type BrandProfile = {
   }>
   /**
    * Background image variants from backgrounds.json.
-   * `file` is an absolute path (resolved by brand-loader).
+   * `file` is a container-relative key (e.g. `brands/acme/backgrounds/bg.png`).
    * Empty array when backgrounds.json is absent (e.g. Volt).
    */
   backgroundVariants: Array<{