fix(GRO-867): proxy logo download through API server — no mixed content

All logo S3 interactions are now server-proxied:
- GET /api/admin/settings/logo streams image bytes directly
  instead of returning a presigned S3 URL to the browser
- Upload already went through POST /api/admin/settings/logo/upload
- Frontend uses relative /api/admin/settings/logo path as img src,
  never a raw S3 URL

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/lib/s3.ts

@@ -68,6 +68,20 @@ export async function deleteObject(key: string): Promise<void> {
   );
 }
 
+/** Read an object from S3 and return its body buffer and content type. */
+export async function getObject(key: string): Promise<{ body: Buffer; contentType: string }> {
+  const client = getS3Client();
+  const response = await client.send(
+    new GetObjectCommand({
+      Bucket: getBucket(),
+      Key: key,
+    })
+  );
+  const body = await response.Body!.transformToBuffer();
+  const contentType = response.ContentType ?? "application/octet-stream";
+  return { body, contentType };
+}
+
 /** Upload an object directly to S3 (server-side only, not a pre-signed URL). */
 export async function putObject(
   key: string,

apps/api/src/routes/settings.ts

@@ -2,7 +2,7 @@ import { Hono } from "hono";
 import { zValidator } from "@hono/zod-validator";
 import { z } from "zod/v3";
 import { eq, getDb, businessSettings } from "@groombook/db";
-import { getPresignedUploadUrl, getPresignedGetUrl, deleteObject, putObject } from "../lib/s3.js";
+import { getPresignedUploadUrl, getPresignedGetUrl, deleteObject, putObject, getObject } from "../lib/s3.js";
 import { requireSuperUser } from "../middleware/rbac.js";
 
 export const settingsRouter = new Hono();
@@ -215,7 +215,8 @@ settingsRouter.post(
 
 /**
  * GET /api/admin/settings/logo
- * Returns a presigned GET URL for the logo.
+ * Proxies the logo from S3 so the browser never sees an S3 URL.
+ * Returns the image bytes with proper Content-Type.
  */
 settingsRouter.get("/logo", async (c) => {
   const db = getDb();
@@ -224,8 +225,10 @@ settingsRouter.get("/logo", async (c) => {
   if (!row) return c.json({ error: "Settings not found" }, 404);
   if (!row.logoKey) return c.json({ error: "No logo on file" }, 404);
 
-  const url = await getPresignedGetUrl(row.logoKey);
-  return c.json({ url, logoKey: row.logoKey });
+  const { body, contentType } = await getObject(row.logoKey);
+  c.header("Content-Type", contentType);
+  c.header("Cache-Control", "public, max-age=86400");
+  return c.body(body);
 });
 
 /**

apps/web/src/pages/Settings.tsx

@@ -89,24 +89,14 @@ export function SettingsPage() {
     fetch("/api/admin/settings")
       .then((r) => r.json())
       .then(async (data) => {
-        let logoUrl: string | null = null;
-        if (data.logoKey) {
-          try {
-            const logoRes = await fetch("/api/admin/settings/logo");
-            if (logoRes.ok) {
-              const logoData = await logoRes.json();
-              logoUrl = logoData.url;
-            }
-          } catch {
-            // ignore
-          }
-        }
+        // The logo is now proxied through the API server so the browser
+        // never receives an S3 URL — use the proxy path directly as the src.
         setForm({
           businessName: data.businessName ?? "GroomBook",
           primaryColor: data.primaryColor ?? "#4f8a6f",
           accentColor: data.accentColor ?? "#8b7355",
           logoKey: data.logoKey ?? null,
-          logoUrl,
+          logoUrl: data.logoKey ? "/api/admin/settings/logo" : null,
           logoBase64: data.logoBase64 ?? null,
           logoMimeType: data.logoMimeType ?? null,
         });
@@ -172,15 +162,7 @@ export function SettingsPage() {
         throw new Error(err?.error ?? "Failed to upload logo");
       }
       const { logoKey } = await uploadRes.json();
-
-      // Fetch the presigned GET URL for display
-      const logoRes = await fetch("/api/admin/settings/logo");
-      if (logoRes.ok) {
-        const logoData = await logoRes.json();
-        setForm((f) => ({ ...f, logoKey, logoUrl: logoData.url, logoBase64: null, logoMimeType: null }));
-      } else {
-        setForm((f) => ({ ...f, logoKey, logoUrl: null, logoBase64: null, logoMimeType: null }));
-      }
+      setForm((f) => ({ ...f, logoKey, logoUrl: "/api/admin/settings/logo", logoBase64: null, logoMimeType: null }));
       setMessage({ type: "success", text: "Logo uploaded." });
       refresh();
     } catch (err: unknown) {