feat: initial Luma implementation

Full self-hosted photo manager with:
- Ingestion worker (chokidar + sharp + exifr, dHash perceptual hashing)
- SQLite schema with WAL mode (photos, tags, collections, duplicate_pairs)
- Express API with keyset pagination, tag/collection/search/date filters
- React + Vite UI: timeline, lightbox, detail panel, tag/collection editors
- Duplicate detection (Union-Find grouping) with review + dismiss UI
- Map view (Leaflet + OpenStreetMap, marker clustering)
- Docker multi-stage build + Compose with inline env config
- GitHub Actions: CI build check + ghcr.io image publish on main/tags

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

worker/index.js

@@ -0,0 +1,60 @@
+import 'dotenv/config';
+import chokidar from 'chokidar';
+import path from 'path';
+import { openDb } from './db.js';
+import { ingestFile, isSupported } from './ingest.js';
+
+const PHOTO_DIR  = process.env.PHOTO_DIR  ?? './photos';
+const DB_PATH    = process.env.DB_PATH    ?? './data/library.db';
+const POSTER_DIR = process.env.POSTER_DIR ?? './data/posters';
+
+const db = openDb(DB_PATH);
+
+console.log(`[worker] watching ${path.resolve(PHOTO_DIR)}`);
+console.log(`[worker] db at ${path.resolve(DB_PATH)} (${db.count()} photos indexed)`);
+
+// Serial queue: chokidar fires many 'add' events at once on startup;
+// process them one at a time to keep memory and I/O pressure low.
+const queue = [];
+let busy = false;
+
+async function drain() {
+  if (busy) return;
+  busy = true;
+  while (queue.length > 0) {
+    const fp = queue.shift();
+    try {
+      await ingestFile(fp, db, POSTER_DIR);
+    } catch (err) {
+      console.error(`[worker] ${path.basename(fp)}: ${err.message}`);
+    }
+  }
+  busy = false;
+}
+
+const watcher = chokidar.watch(PHOTO_DIR, {
+  persistent: true,
+  ignoreInitial: false,
+  awaitWriteFinish: { stabilityThreshold: 2000, pollInterval: 100 },
+  ignored: /(^|[/\\])\../,   // skip dotfiles
+});
+
+watcher.on('add', (fp) => {
+  if (!isSupported(fp)) return;
+  queue.push(path.resolve(fp));
+  drain();
+});
+
+watcher.on('unlink', (fp) => {
+  const resolved = path.resolve(fp);
+  db.removePhoto(resolved);
+  console.log(`[worker] removed ${path.basename(fp)}`);
+});
+
+watcher.on('error', (err) => console.error('[worker] watcher error:', err));
+
+process.on('SIGINT', () => {
+  console.log('\n[worker] shutting down');
+  watcher.close();
+  process.exit(0);
+});