dsh-remote 0.1.0: master/slave remote control for DSH

- authenticated WebSocket link (dependency-free RFC6455 + stream mux), pairing
  codes, per-device keys (hashed), revoke/remove
- /r/<device>/ proxy of the full DSH UI (HTTP, Remote WebSocket, SSE) with
  per-device cookie minting; slave->slave relay through the master
- Devices sidebar panel (all devices' sessions, new session on device),
  Remote devices settings page, finished-session toasts
- plugin + config sync master->slave: registry bundles via pluginManager,
  link: plugins as tarballs, cordis.patch.yml into a managed bundle layer
  (!!js preserved), allow/deny, opt-in per-secret credential sync
- deploy helpers + e2e probes, unit tests

deploy/push-slave.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# Dev helper: copy this checkout to a slave's ~/.dsh/plugins/dsh-remote and restart its dsh.
+#   deploy/push-slave.sh agent@192.168.0.110
+set -euo pipefail
+HOST="${1:?usage: push-slave.sh user@host}"
+DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+O=(-o BatchMode=yes -o ConnectTimeout=5 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o LogLevel=ERROR)
+tar --exclude=.git --exclude=node_modules -C "$DIR" -czf - . | timeout 20 ssh "${O[@]}" "$HOST" \
+  'mkdir -p ~/.dsh/plugins/dsh-remote && tar -xzf - -C ~/.dsh/plugins/dsh-remote'
+timeout 45 ssh "${O[@]}" "$HOST" 'export PATH=$HOME/.local/bin:$PATH XDG_RUNTIME_DIR=/run/user/$(id -u)
+systemctl --user restart dsh
+for i in $(seq 1 40); do curl -s -m 2 -o /dev/null http://127.0.0.1:3081/ && break; sleep 0.5; done
+echo "slave dsh: $(systemctl --user is-active dsh)"'