feat: Archivum skeleton — Go/GraphQL backend + Vue 3 PWA frontend

Full project scaffold: multi-stage Dockerfile (ARM64/AMD64), AsciiDoc↔TipTap
bridge, Setup Wizard, CodeMirror source editor, Git-backed storage layer,
LDAP+JWT auth skeleton, Tailwind mobile-first layout, and VS Code build/push
tasks targeting registry at 192.168.0.19:5000.

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

docker/Dockerfile

@@ -0,0 +1,42 @@
+# ── Stage 1: Build frontend ───────────────────────────────────────────────────
+FROM node:20-alpine AS frontend-builder
+
+WORKDIR /app/frontend
+COPY frontend/package*.json ./
+RUN npm ci
+COPY frontend/ ./
+RUN npm run build
+
+# ── Stage 2: Build backend ────────────────────────────────────────────────────
+FROM golang:1.22-alpine AS backend-builder
+
+WORKDIR /app/backend
+COPY backend/go.mod backend/go.sum ./
+RUN go mod download
+COPY backend/ ./
+# CGO disabled — pure Go SQLite (modernc.org/sqlite).
+RUN CGO_ENABLED=0 go build -ldflags="-s -w" -o /archivum ./cmd/server
+
+# ── Stage 3: Runtime image ────────────────────────────────────────────────────
+FROM alpine:3.20
+
+# Allow PUID/PGID override at runtime.
+ARG PUID=1000
+ARG PGID=1000
+
+RUN addgroup -g "${PGID}" archivum \
+ && adduser -u "${PUID}" -G archivum -s /sbin/nologin -D archivum
+
+# Embed frontend into the binary's working directory.
+COPY --from=frontend-builder /app/frontend/dist /srv/archivum/ui
+COPY --from=backend-builder  /archivum            /usr/local/bin/archivum
+
+# Volumes: config and data live outside the image.
+VOLUME ["/config", "/data"]
+
+ENV DOCKER_PATH=/config
+
+USER archivum
+EXPOSE 4000
+
+ENTRYPOINT ["/usr/local/bin/archivum"]