Add platform-dash: S3 artifact browser for Garage object store

Lightweight Next.js app for browsing, uploading, and downloading
artifacts from the cluster-local Garage S3 bucket. Uses the harness
design system. Features:
- File/folder browser with breadcrumb navigation
- Drag-and-drop upload
- Download and delete
- Ingress at platform.coreworlds.io (internal-only)

Also adds platform-dash to CI/deploy workflows.

apps/platform-dash/src/app/api/s3/route.ts

@@ -0,0 +1,90 @@
+import { NextRequest, NextResponse } from "next/server";
+import {
+  S3Client,
+  ListObjectsV2Command,
+  PutObjectCommand,
+  DeleteObjectCommand,
+} from "@aws-sdk/client-s3";
+
+const BUCKET = process.env.S3_BUCKET || "artifacts";
+
+function getClient() {
+  return new S3Client({
+    endpoint: process.env.S3_ENDPOINT || "http://garage.platform.svc:3900",
+    region: process.env.S3_REGION || "garage",
+    credentials: {
+      accessKeyId: process.env.S3_ACCESS_KEY_ID || "",
+      secretAccessKey: process.env.S3_SECRET_ACCESS_KEY || "",
+    },
+    forcePathStyle: true,
+  });
+}
+
+// GET — list objects
+export async function GET(request: NextRequest) {
+  const prefix = request.nextUrl.searchParams.get("prefix") || "";
+  const client = getClient();
+
+  try {
+    const result = await client.send(
+      new ListObjectsV2Command({ Bucket: BUCKET, Prefix: prefix || undefined })
+    );
+
+    const objects = (result.Contents || []).map((obj) => ({
+      key: obj.Key,
+      size: obj.Size,
+      lastModified: obj.LastModified?.toISOString(),
+    }));
+
+    return NextResponse.json({ objects });
+  } catch (e: unknown) {
+    const msg = e instanceof Error ? e.message : "S3 error";
+    return NextResponse.json({ error: msg }, { status: 500 });
+  }
+}
+
+// PUT — upload object
+export async function PUT(request: NextRequest) {
+  const key = request.nextUrl.searchParams.get("key");
+  if (!key) {
+    return NextResponse.json({ error: "key required" }, { status: 400 });
+  }
+
+  const body = await request.arrayBuffer();
+  const client = getClient();
+
+  try {
+    await client.send(
+      new PutObjectCommand({
+        Bucket: BUCKET,
+        Key: key,
+        Body: Buffer.from(body),
+        ContentType: request.headers.get("content-type") || "application/octet-stream",
+      })
+    );
+    return NextResponse.json({ ok: true });
+  } catch (e: unknown) {
+    const msg = e instanceof Error ? e.message : "Upload failed";
+    return NextResponse.json({ error: msg }, { status: 500 });
+  }
+}
+
+// DELETE — remove object
+export async function DELETE(request: NextRequest) {
+  const key = request.nextUrl.searchParams.get("key");
+  if (!key) {
+    return NextResponse.json({ error: "key required" }, { status: 400 });
+  }
+
+  const client = getClient();
+
+  try {
+    await client.send(
+      new DeleteObjectCommand({ Bucket: BUCKET, Key: key })
+    );
+    return NextResponse.json({ ok: true });
+  } catch (e: unknown) {
+    const msg = e instanceof Error ? e.message : "Delete failed";
+    return NextResponse.json({ error: msg }, { status: 500 });
+  }
+}