Add reMarkable backup system with web UI

- Docker container with rmapi cloud backup, PDF conversion pipeline
- Web UI: file browser, multi-select, delete/move, thumbnail preview
- Sync: backup from reMarkable cloud, rmdoc→PDF conversion via rmc+Inkscape
- Excluded-files mechanism to prevent deleted items from returning after sync

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

remarkable/scripts/backup-official-cloud.sh

@@ -0,0 +1,113 @@
+#!/usr/bin/env bash
+# reMarkable Backup (offizielle Cloud via rmapi)
+#
+# Ziel:
+# - Inkrementeller Download in "current/".
+# - Datierte Snapshots in "snapshots/YYYY-MM-DD_HHMMSS/".
+# - Versionierung via Hardlinks (unveraenderte Dateien belegen kaum Zusatzplatz).
+#
+# Nutzung:
+#   ./backup-official-cloud.sh /www/remarkable/notizen /
+#
+set -euo pipefail
+
+BASE_DIR="${1:-/www/remarkable/notizen}"
+REMOTE_DIR="${2:-/}"
+TIMESTAMP="$(date +%F_%H%M%S)"
+
+CURRENT_DIR="${BASE_DIR}/current"
+SNAPSHOT_ROOT="${BASE_DIR}/snapshots"
+SNAPSHOT_DIR="${SNAPSHOT_ROOT}/${TIMESTAMP}"
+LATEST_LINK="${SNAPSHOT_ROOT}/latest"
+LOG_DIR="${BASE_DIR}/logs"
+LOCK_FILE="${BASE_DIR}/.backup.lock"
+
+# Optional: Pfad, der ein echter Mountpoint sein muss (z. B. /www/remarkable/notizen).
+# Wenn gesetzt und kein Mountpoint, wird abgebrochen (sicher gegen "auf Root-FS schreiben").
+MOUNT_CHECK_PATH="${MOUNT_CHECK_PATH:-}"
+
+# Optional: Anzahl alter Snapshots behalten (0 = unbegrenzt).
+SNAPSHOT_KEEP="${SNAPSHOT_KEEP:-30}"
+
+mkdir -p "${CURRENT_DIR}" "${SNAPSHOT_ROOT}" "${LOG_DIR}"
+
+if [[ -n "${MOUNT_CHECK_PATH}" ]] && ! mountpoint -q "${MOUNT_CHECK_PATH}"; then
+  echo "Fehler: ${MOUNT_CHECK_PATH} ist nicht gemountet. Backup abgebrochen."
+  exit 1
+fi
+
+if ! command -v rmapi >/dev/null 2>&1; then
+  echo "Fehler: rmapi nicht im PATH."
+  exit 1
+fi
+
+if ! command -v rsync >/dev/null 2>&1; then
+  echo "Fehler: rsync fehlt. Bitte installieren."
+  exit 1
+fi
+
+exec 9>"${LOCK_FILE}"
+if ! flock -n 9; then
+  echo "Backup laeuft bereits (Lock: ${LOCK_FILE})."
+  exit 1
+fi
+
+LOG_FILE="${LOG_DIR}/backup-${TIMESTAMP}.log"
+exec > >(tee -a "${LOG_FILE}") 2>&1
+
+echo "== reMarkable Backup Start =="
+echo "Base: ${BASE_DIR}"
+echo "Remote: ${REMOTE_DIR}"
+echo "Zeit: ${TIMESTAMP}"
+
+MGET_FLAGS=(-i)
+if [[ "${BACKUP_FULL:-}" == "1" ]]; then
+  MGET_FLAGS=()
+fi
+if [[ "${BACKUP_MIRROR_DELETE:-}" == "1" ]]; then
+  MGET_FLAGS+=(-d)
+fi
+
+echo "1) Aktualisiere current/ via rmapi mget ${MGET_FLAGS[*]:-(none)} ..."
+rmapi mget "${MGET_FLAGS[@]}" -o "${CURRENT_DIR}" "${REMOTE_DIR}"
+
+# Leere Ordner anlegen (rmapi mget erstellt keine leeren Verzeichnisse)
+echo "1b) Lege fehlende Ordner an ..."
+rmapi find "${REMOTE_DIR}" 2>/dev/null | grep '^\[d\]' | sed 's/^\[d\] *//' | while read -r DIR; do
+  LOCAL_DIR="${CURRENT_DIR}/${DIR}"
+  mkdir -p "${LOCAL_DIR}"
+done
+
+echo "2) Erzeuge Snapshot: ${SNAPSHOT_DIR}"
+mkdir -p "${SNAPSHOT_DIR}"
+
+if [[ -L "${LATEST_LINK}" ]] && [[ -d "$(readlink -f "${LATEST_LINK}")" ]]; then
+  PREV_SNAPSHOT="$(readlink -f "${LATEST_LINK}")"
+  rsync -a --delete --link-dest="${PREV_SNAPSHOT}" "${CURRENT_DIR}/" "${SNAPSHOT_DIR}/"
+else
+  rsync -a --delete "${CURRENT_DIR}/" "${SNAPSHOT_DIR}/"
+fi
+
+ln -sfn "${SNAPSHOT_DIR}" "${LATEST_LINK}"
+
+if [[ "${SNAPSHOT_KEEP}" =~ ^[0-9]+$ ]] && (( SNAPSHOT_KEEP > 0 )); then
+  echo "3) Pruefe Retention (keep=${SNAPSHOT_KEEP}) ..."
+  mapfile -t SNAPSHOTS < <(ls -1 "${SNAPSHOT_ROOT}" | grep -E '^[0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{6}$' | sort)
+  if (( ${#SNAPSHOTS[@]} > SNAPSHOT_KEEP )); then
+    DELETE_COUNT=$(( ${#SNAPSHOTS[@]} - SNAPSHOT_KEEP ))
+    for OLD in "${SNAPSHOTS[@]:0:DELETE_COUNT}"; do
+      rm -rf "${SNAPSHOT_ROOT}/${OLD}"
+      echo "   entfernt: ${SNAPSHOT_ROOT}/${OLD}"
+    done
+  fi
+fi
+
+# PDF-Konvertierung
+if command -v remarkable-convert.sh >/dev/null 2>&1; then
+  echo "4) Konvertiere .rmdoc zu PDF ..."
+  remarkable-convert.sh "${CURRENT_DIR}"
+fi
+
+echo "== Backup fertig =="
+echo "Current:  ${CURRENT_DIR}"
+echo "Snapshot: ${SNAPSHOT_DIR}"