Initial SDP skeleton

Sandbox Deployment Platform — Go control plane + agents, NextJS dashboard,
nginx reverse proxy. Cross-compile via Docker; deploy via sshpass to
172.18.136.92 (micro) and 172.18.139.186 (gateway).

- control-plane: HTTP API, WS hub, SQLite (modernc.org/sqlite) for
  progress, .log files for log persistence
- agent-micro / agent-gateway: alpine:3.20 + bind-mounted repo,
  binary exec'd in container, no Dockerfile build step
- dashboard: NextJS static export + shadcn/ui components, single
  WebSocket hook
- docker-compose.yml: three services on alpine:latest with docker
  socket bind for agents
- scripts/: build.sh (golang:1.23-alpine cross-compile), deploy.sh,
  patch-nginx.sh (idempotent nginx splice), ssh wrappers

Runtime model: pass-through Bitbucket creds per deploy, never logged or
persisted on the agent. Control plane never touches git or docker
directly — agents do all the work locally.

scripts/ssh-92.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+# SSH into the micro VM (172.18.136.92). Wraps ssh with the known password.
+# Usage: scripts/ssh-92.sh [extra ssh args...]
+set -euo pipefail
+cd "$(dirname "$0")/.."
+
+HOST="${SDP_92_HOST:-administrator@172.18.136.92}"
+PASS="${SDP_92_PASS:-password}"
+
+if ! command -v sshpass >/dev/null 2>&1; then
+  echo "sshpass not found. Install with: brew install sshpass" >&2
+  exit 1
+fi
+
+exec sshpass -p "$PASS" ssh \
+  -o StrictHostKeyChecking=no \
+  -o UserKnownHostsFile=/dev/null \
+  -o LogLevel=ERROR \
+  "$HOST" "$@"