feat(scripts): add --deploy flag to build-linux-docker.sh

Deploys wzp-relay to both relay servers after building:
- manwe@manwehs:/home/manwe/wzp (tmux session 5)
- manwe@pangolin.manko.yoga:/home/manwe/wzp-linux (tmux session 0)

Captures current relay args from /proc, stops via tmux C-c, restarts
with same args. Also fixes hardcoded branch default to use current git branch.

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

scripts/build-linux-docker.sh

@@ -10,6 +10,7 @@ set -euo pipefail
 #   ./scripts/build-linux-docker.sh --pull       Git pull before building
 #   ./scripts/build-linux-docker.sh --clean      Clean Rust target cache
 #   ./scripts/build-linux-docker.sh --install    Download binaries locally after build
+#   ./scripts/build-linux-docker.sh --deploy     Download + deploy wzp-relay to relay servers
 
 REMOTE_HOST="SepehrHomeserverdk"
 BASE_DIR="/mnt/storage/manBuilder"
@@ -21,17 +22,26 @@ SSH_OPTS="-o ConnectTimeout=15 -o ServerAliveInterval=15 -o ServerAliveCountMax=
 # (opus-DRED-v2 as of 2026-04-11). Override with `WZP_BRANCH=<name> ./build-linux-docker.sh`
 # if you need a different one — e.g. to rebuild the relay from a feature
 # branch for A/B testing.
-WZP_BRANCH="${WZP_BRANCH:-opus-DRED-v2}"
+WZP_BRANCH="${WZP_BRANCH:-$(git -C "$(dirname "$0")/.." branch --show-current 2>/dev/null || echo "experimental-ui")}"
+
+# Relay servers to deploy to when --deploy is passed.
+# Format: "user@host:binary_dir:tmux_session"
+RELAY_SERVERS=(
+    "manwe@manwehs:/home/manwe/wzp:5"
+    "manwe@pangolin.manko.yoga:/home/manwe/wzp-linux:0"
+)
 
 DO_PULL=1
 DO_CLEAN=0
 DO_INSTALL=0
+DO_DEPLOY=0
 for arg in "$@"; do
     case "$arg" in
-        --pull) DO_PULL=1 ;;
+        --pull)    DO_PULL=1 ;;
         --no-pull) DO_PULL=0 ;;
-        --clean) DO_CLEAN=1 ;;
+        --clean)   DO_CLEAN=1 ;;
         --install) DO_INSTALL=1 ;;
+        --deploy)  DO_DEPLOY=1; DO_INSTALL=1 ;;
     esac
 done
 
@@ -149,6 +159,41 @@ echo "  Monitor:  ssh $REMOTE_HOST 'tail -f /tmp/wzp-linux-build.log'"
 echo "  Status:   ssh $REMOTE_HOST 'tail -5 /tmp/wzp-linux-build.log'"
 echo ""
 
+# Deploy wzp-relay to a single relay server.
+# $1 = "user@host"  $2 = binary_dir  $3 = tmux_session
+deploy_relay() {
+    local TARGET="$1"
+    local BINARY_DIR="$2"
+    local TMUX_SESSION="$3"
+    local DEPLOY_OPTS="-o ConnectTimeout=15 -o StrictHostKeyChecking=accept-new -o LogLevel=ERROR"
+
+    log "Deploying wzp-relay to $TARGET ($BINARY_DIR) ..."
+
+    # Copy new binary atomically
+    scp $DEPLOY_OPTS "$LOCAL_OUTPUT/wzp-relay" "$TARGET:$BINARY_DIR/wzp-relay.new"
+    ssh $DEPLOY_OPTS "$TARGET" "chmod +x $BINARY_DIR/wzp-relay.new && mv $BINARY_DIR/wzp-relay.new $BINARY_DIR/wzp-relay"
+
+    # Capture current args, stop, restart in same tmux session
+    ssh $DEPLOY_OPTS "$TARGET" bash <<DEPLOY
+set -euo pipefail
+RELAY_PID=\$(pgrep -f './wzp-relay' | head -1 || true)
+if [ -z "\$RELAY_PID" ]; then
+    echo "WARNING: no running wzp-relay found on $TARGET — binary replaced, start it manually"
+    exit 0
+fi
+# Capture args from /proc (everything after the binary name)
+RELAY_ARGS=\$(tr '\\0' ' ' < /proc/\$RELAY_PID/cmdline | sed 's|^[^ ]* ||; s| *\$||')
+echo "Stopping relay PID \$RELAY_PID (args: \$RELAY_ARGS)"
+tmux send-keys -t $TMUX_SESSION C-c 2>/dev/null || kill -TERM \$RELAY_PID 2>/dev/null || true
+sleep 2
+echo "Starting new relay..."
+tmux send-keys -t $TMUX_SESSION "cd $BINARY_DIR && ./wzp-relay \$RELAY_ARGS" Enter 2>/dev/null || true
+echo "Deploy done on $TARGET"
+DEPLOY
+
+    log "Deployed to $TARGET"
+}
+
 # Optionally wait and download
 if [ "$DO_INSTALL" = "1" ]; then
     log "Waiting for build..."
@@ -170,5 +215,19 @@ if [ "$DO_INSTALL" = "1" ]; then
         log "Done! Binaries in $LOCAL_OUTPUT/"
     else
         err "Build failed"
+        exit 1
     fi
 fi
+
+# Deploy to relay servers
+if [ "$DO_DEPLOY" = "1" ]; then
+    if [ ! -f "$LOCAL_OUTPUT/wzp-relay" ]; then
+        err "wzp-relay binary not found in $LOCAL_OUTPUT — install step may have failed"
+        exit 1
+    fi
+    for SERVER in "${RELAY_SERVERS[@]}"; do
+        IFS=: read -r TARGET BINARY_DIR TMUX_SESSION <<< "$SERVER"
+        deploy_relay "$TARGET" "$BINARY_DIR" "$TMUX_SESSION"
+    done
+    log "All relay servers updated!"
+fi