feat(icons): filesystem icon-set store (bundled read-only + uploads)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/icons/sets.js

@@ -0,0 +1,52 @@
+// lib/icons/sets.js
+import { mkdir, readdir, readFile, rm, writeFile } from 'node:fs/promises';
+import path from 'node:path';
+
+const BUNDLED_SET = 'devices';              // read-only, ships in public/icons/devices
+let setsDir = process.env.ICON_SETS_DIR || '/var/lib/void/icon-sets';
+let bundledDir = path.resolve('public/icons/devices');
+export function _setDirs({ setsDir: s, bundledDir: b }) { if (s) setsDir = s; if (b) bundledDir = b; }
+
+const SLUG = /^[a-z0-9-]+$/;
+const FILE = /^[a-z0-9-]+\.(svg|png|jpg|jpeg)$/;
+function okSet(s) { return SLUG.test(s); }
+
+async function listDir(dir) {
+  try { return (await readdir(dir)).filter(f => FILE.test(f)).sort(); } catch { return []; }
+}
+
+export async function listSets() {
+  const out = [{ set: BUNDLED_SET, readonly: true, icons: await listDir(bundledDir) }];
+  let uploaded = [];
+  try { uploaded = await readdir(setsDir, { withFileTypes: true }); } catch { /* none yet */ }
+  for (const d of uploaded) {
+    if (d.isDirectory() && okSet(d.name) && d.name !== BUNDLED_SET) {
+      out.push({ set: d.name, readonly: false, icons: await listDir(path.join(setsDir, d.name)) });
+    }
+  }
+  return out;
+}
+
+// Resolve an on-disk path for serving. Throws on bad slugs.
+export function iconPath(set, file) {
+  if (!okSet(set) || !FILE.test(file)) throw new Error('bad_slug');
+  return set === BUNDLED_SET ? path.join(bundledDir, file) : path.join(setsDir, set, file);
+}
+
+export async function readIcon(set, file) {
+  return readFile(iconPath(set, file));
+}
+
+export async function writeIcon(set, name, buffer) {
+  if (set === BUNDLED_SET) throw new Error('reserved_set');
+  if (!okSet(set) || !FILE.test(name)) throw new Error('bad_slug');
+  const dir = path.join(setsDir, set);
+  await mkdir(dir, { recursive: true });
+  await writeFile(path.join(dir, name), buffer);
+}
+
+export async function deleteSet(set) {
+  if (set === BUNDLED_SET) throw new Error('reserved_set');
+  if (!okSet(set)) throw new Error('bad_slug');
+  await rm(path.join(setsDir, set), { recursive: true, force: true });
+}