feat: initial vpndock stack

HAProxy SOCKS5 entry point + scalable purevpn-cli/microsocks exit nodes.
Supports up to 10 simultaneous connections (PureVPN limit), random location
selection from a predefined pool, and automatic reconnect to an unused
location on server-side drop.

haproxy/haproxy.cfg

@@ -0,0 +1,55 @@
+global
+    log stdout format raw local0 info
+    maxconn 50000
+    # Run as non-root inside the container
+    # user haproxy
+    # group haproxy
+
+defaults
+    log     global
+    mode    tcp
+    option  tcplog
+    option  dontlognull
+    retries 3
+    timeout connect  10s
+    timeout client   1m
+    timeout server   1m
+    timeout check    5s
+
+# ── Docker embedded DNS ───────────────────────────────────────────────────────
+resolvers docker_dns
+    nameserver dns1 127.0.0.11:53
+    resolve_retries 10
+    timeout resolve 1s
+    timeout retry   1s
+    hold valid      10s
+    hold other      10s
+    hold refused    10s
+    hold nx         10s
+
+# ── SOCKS5 frontend (browsers / curl / etc. connect here) ────────────────────
+frontend socks5_in
+    bind *:1080
+    default_backend vpn_exit_nodes
+
+# ── Round-robin across all vpn-node containers ───────────────────────────────
+backend vpn_exit_nodes
+    balance roundrobin
+    # server-template creates up to 10 slots; Docker DNS fills them dynamically
+    # as you scale with: docker compose up --scale vpn-node=N (max 10)
+    server-template vpn 1-10 vpn-node:1080 \
+        resolvers docker_dns \
+        resolve-prefer ipv4 \
+        init-addr none \
+        check inter 20s fall 2 rise 2
+
+# ── Stats page — http://<host>:8404/stats ─────────────────────────────────────
+frontend stats
+    bind *:8404
+    mode http
+    stats enable
+    stats uri /stats
+    stats refresh 5s
+    stats show-legends
+    stats show-node
+    stats auth admin:admin     # change this password