Add multi-platform game support with per-OS download detection

- Detect Windows (.zip), Linux (.tar.gz), and macOS (.dmg / .app bundle) game archives during scan
- Store GameFile[] with platform metadata in DB instead of plain zipFiles[]
- Stream .app bundles as on-the-fly zip archives via archiver
- Show WIN/LIN/MAC platform badge pills on GameCard and SeriesCard
- Auto-select the download matching the user's OS in GameDetailModal
- Persist cover URL to DB immediately on upload (no re-scan needed)
- Backward-compatible: legacy zipFiles entries map to platform 'windows'

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/api/file/route.ts

@@ -1,6 +1,7 @@
 import { NextRequest, NextResponse } from 'next/server'
 import fs from 'fs'
 import path from 'path'
+import archiver from 'archiver'
 import { getLibrary, resolveLibraryRoot, resolveAndJail } from '@/lib/libraries'
 import { requireLibraryAccess } from '@/lib/auth'
 
@@ -20,13 +21,22 @@ const MIME_TYPES: Record<string, string> = {
   '.tiff': 'image/tiff',
   '.tif': 'image/tiff',
   '.zip': 'application/zip',
+  '.dmg': 'application/x-apple-diskimage',
+  '.gz': 'application/gzip',
 }
 
 function getMimeType(filePath: string): string {
+  // Special-case .tar.gz before checking the last extension
+  if (filePath.toLowerCase().endsWith('.tar.gz')) return 'application/gzip'
   const ext = path.extname(filePath).toLowerCase()
   return MIME_TYPES[ext] ?? 'application/octet-stream'
 }
 
+function isDownloadAttachment(filePath: string): boolean {
+  const lower = filePath.toLowerCase()
+  return lower.endsWith('.zip') || lower.endsWith('.tar.gz') || lower.endsWith('.dmg')
+}
+
 export async function GET(request: NextRequest) {
   const { searchParams } = request.nextUrl
   const libraryId = searchParams.get('libraryId')
@@ -60,6 +70,25 @@ export async function GET(request: NextRequest) {
     return NextResponse.json({ error: 'File not found' }, { status: 404 })
   }
 
+  // .app bundle: stream the directory as a zip archive on the fly
+  if (stat.isDirectory() && subpath.toLowerCase().endsWith('.app')) {
+    const bundleName = path.basename(filePath)
+    const zipName = `${bundleName}.zip`
+
+    const archive = archiver('zip', { zlib: { level: 6 } })
+    archive.directory(filePath, bundleName)
+    archive.finalize()
+
+    return new NextResponse(archive as unknown as ReadableStream, {
+      status: 200,
+      headers: {
+        'Content-Type': 'application/zip',
+        'Content-Disposition': `attachment; filename="${encodeURIComponent(zipName)}"`,
+        'Cache-Control': 'no-store',
+      },
+    })
+  }
+
   if (!stat.isFile()) {
     return NextResponse.json({ error: 'Not a file' }, { status: 400 })
   }
@@ -68,9 +97,7 @@ export async function GET(request: NextRequest) {
   const fileSize = stat.size
   const rangeHeader = request.headers.get('range')
 
-  // Handle ZIP as a download
-  const isZip = path.extname(filePath).toLowerCase() === '.zip'
-  const contentDisposition = isZip
+  const contentDisposition = isDownloadAttachment(filePath)
     ? `attachment; filename="${encodeURIComponent(path.basename(filePath))}"`
     : `inline; filename="${encodeURIComponent(path.basename(filePath))}"`