feat: worst-scan fansub web — initial release

Posts engine (SQLite + auto-publisher via poller), public feed with
clickable tags, reader, admin panel, submit/search/queue tools.
BFF proxy to pipeline API. Clean dark design. Docker-ready.

src/lib/cover-cache.ts

@@ -0,0 +1,64 @@
+import fs from "fs"
+import path from "path"
+
+const COVERS_DIR = process.env.COVERS_DIR || path.join(process.cwd(), "data", "covers")
+
+function ensureDir() {
+  fs.mkdirSync(COVERS_DIR, { recursive: true })
+}
+
+function extFromContentType(ct: string | null): string {
+  if (!ct) return ".jpg"
+  const m = ct.match(/image\/(\w+)/)
+  if (!m) return ".jpg"
+  const exts: Record<string, string> = {
+    jpeg: ".jpg",
+    png: ".png",
+    webp: ".webp",
+    gif: ".gif",
+  }
+  return exts[m[1]] || ".jpg"
+}
+
+export async function cacheCover(gid: string, proxyUrl: string): Promise<string | null> {
+  ensureDir()
+  try {
+    const res = await fetch(proxyUrl, { signal: AbortSignal.timeout(15000) })
+    if (!res.ok) return null
+
+    const buffer = Buffer.from(await res.arrayBuffer())
+    const ext = extFromContentType(res.headers.get("content-type"))
+    const filePath = path.join(COVERS_DIR, `${gid}${ext}`)
+
+    fs.writeFileSync(filePath, buffer)
+    return filePath
+  } catch {
+    return null
+  }
+}
+
+export function getCoverPath(gid: string): string | null {
+  ensureDir()
+  const files = fs.readdirSync(COVERS_DIR).filter((f) => f.startsWith(gid))
+  if (files.length === 0) return null
+  return path.join(COVERS_DIR, files[0])
+}
+
+export function getCoverContentType(gid: string): string {
+  const fp = getCoverPath(gid)
+  if (!fp) return "image/jpeg"
+  const ext = path.extname(fp).toLowerCase()
+  const m: Record<string, string> = {
+    ".jpg": "image/jpeg",
+    ".jpeg": "image/jpeg",
+    ".png": "image/png",
+    ".webp": "image/webp",
+    ".gif": "image/gif",
+  }
+  return m[ext] || "image/jpeg"
+}
+
+export function deleteCover(gid: string): void {
+  const fp = getCoverPath(gid)
+  if (fp) fs.unlinkSync(fp)
+}