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>

Dockerfile

@@ -0,0 +1,40 @@
+# ── Stage 1: build client ────────────────────────────────────────────────────
+FROM node:22-alpine AS builder
+
+# Build tools needed by better-sqlite3 native addon
+RUN apk add --no-cache python3 make g++
+
+WORKDIR /app
+COPY package*.json ./
+RUN npm ci
+COPY . .
+RUN npm run build
+
+# ── Stage 2: runtime ─────────────────────────────────────────────────────────
+FROM node:22-alpine
+
+RUN apk add --no-cache python3 make g++
+
+WORKDIR /app
+
+COPY package*.json ./
+# Reinstall in the runtime image so native addons compile for this arch
+RUN npm ci --omit=dev
+
+COPY --from=builder /app/dist ./dist
+COPY worker ./worker
+COPY server ./server
+
+ENV PORT=3000 \
+    DB_PATH=/data/library.db \
+    POSTER_DIR=/data/posters \
+    PHOTO_DIR=/photos \
+    NODE_ENV=production
+
+EXPOSE 3000
+
+# /data  — SQLite database + generated thumbnails (mount a named volume)
+# /photos — read-only source photo directory (bind-mount from host)
+VOLUME ["/data", "/photos"]
+
+CMD ["node", "server/index.js"]