add series grouping, cover upload, and multi-zip download to games library

- Series grouping: a top-level folder with no .zip but game subfolders is
  now treated as a GameSeries. Clicking a series drills into it with a
  breadcrumb; a game-count badge distinguishes series cards from game cards.
  Series fall back to the first game's cover when no series-level cover exists.
- Cover upload: new POST /api/game-cover endpoint writes cover.jpg or
  widecover.jpg directly into the game/series folder (re-encoded via sharp).
  A kebab menu on GameDetailModal opens an Edit Images panel showing previews
  and upload/replace buttons for both cover and wide cover.
- Multi-zip download: Game.zipFiles replaces zipPath and includes all .zip
  files in the folder. A single zip shows the existing download button; multiple
  zips render a split button — primary action downloads the first file, a
  dropdown arrow lists all files by name.

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

src/app/api/game-cover/route.ts

@@ -0,0 +1,99 @@
+import path from 'path'
+import fs from 'fs'
+import sharp from 'sharp'
+import { NextRequest, NextResponse } from 'next/server'
+import { getLibrary, resolveLibraryRoot, resolveAndJail } from '@/lib/libraries'
+
+const MAX_COVER_BYTES = 10 * 1024 * 1024 // 10 MB
+
+type CoverType = 'cover' | 'widecover'
+
+function isCoverType(s: string | null): s is CoverType {
+  return s === 'cover' || s === 'widecover'
+}
+
+export async function POST(request: NextRequest) {
+  const { searchParams } = request.nextUrl
+  const libraryId = searchParams.get('libraryId')
+  const itemId = searchParams.get('itemId')
+  const coverType = searchParams.get('coverType')
+
+  if (!libraryId || !itemId) {
+    return NextResponse.json({ error: 'Missing libraryId or itemId' }, { status: 400 })
+  }
+  if (!isCoverType(coverType)) {
+    return NextResponse.json({ error: 'coverType must be "cover" or "widecover"' }, { status: 400 })
+  }
+
+  const library = getLibrary(libraryId)
+  if (!library) {
+    return NextResponse.json({ error: 'Library not found' }, { status: 404 })
+  }
+  if (library.type !== 'games') {
+    return NextResponse.json({ error: 'Library is not a games library' }, { status: 400 })
+  }
+
+  const libraryRoot = resolveLibraryRoot(library)
+  const folderPath = decodeURIComponent(itemId)
+
+  let resolvedDir: string
+  try {
+    resolvedDir = resolveAndJail(libraryRoot, folderPath)
+  } catch {
+    return NextResponse.json({ error: 'Invalid item path' }, { status: 400 })
+  }
+
+  if (!fs.existsSync(resolvedDir)) {
+    return NextResponse.json({ error: 'Game folder not found' }, { status: 404 })
+  }
+
+  let formData: FormData
+  try {
+    formData = await request.formData()
+  } catch {
+    return NextResponse.json({ error: 'Invalid form data' }, { status: 400 })
+  }
+
+  const file = formData.get('cover')
+  if (!(file instanceof File)) {
+    return NextResponse.json({ error: 'cover file is required' }, { status: 400 })
+  }
+
+  if (file.size > MAX_COVER_BYTES) {
+    return NextResponse.json({ error: 'File too large. Maximum size is 10 MB.' }, { status: 400 })
+  }
+
+  const rawBuffer = Buffer.from(await file.arrayBuffer())
+
+  let processedBuffer: Buffer
+  try {
+    processedBuffer = await sharp(rawBuffer).jpeg({ quality: 90 }).toBuffer()
+  } catch {
+    return NextResponse.json({ error: 'Invalid or corrupt image file.' }, { status: 400 })
+  }
+
+  const destFilename = `${coverType}.jpg`
+  const destPath = path.join(resolvedDir, destFilename)
+
+  // Remove any existing file with the same base name but a different extension
+  const basePattern = new RegExp(`^${coverType}\\.`, 'i')
+  try {
+    for (const f of fs.readdirSync(resolvedDir)) {
+      if (basePattern.test(f) && f.toLowerCase() !== destFilename) {
+        fs.unlinkSync(path.join(resolvedDir, f))
+      }
+    }
+  } catch { /* ignore */ }
+
+  fs.writeFileSync(destPath, processedBuffer)
+
+  const relPath = path.join(folderPath, destFilename)
+
+  // cover uses the thumbnail endpoint; widecover is served directly
+  const url =
+    coverType === 'cover'
+      ? `/api/thumbnail?libraryId=${encodeURIComponent(libraryId)}&path=${encodeURIComponent(relPath)}`
+      : `/api/file?libraryId=${encodeURIComponent(libraryId)}&path=${encodeURIComponent(relPath)}`
+
+  return NextResponse.json({ url }, { status: 200 })
+}