feat(build): add remote-build-display-control.sh for workstation → Mac builds

Copies display_control.m to laptop 01 via SSH, compiles universal binary
(x86_64 + arm64) on the remote Mac, pulls binary back to resources/bin/.
Defaults to 192.168.32.101; accepts optional IP override as $1.

README: restructure display_control build section — Option A (remote from
workstation, preferred) and Option B (direct on Mac).

scripts/remote-build-display-control.sh

@@ -0,0 +1,94 @@
+#!/usr/bin/env bash
+# scripts/remote-build-display-control.sh
+# Build the display_control universal binary on a remote Mac via SSH,
+# then pull the result back to resources/bin/display_control.
+#
+# Use this from the Linux workstation when you don't have a Mac locally.
+# The target Mac must have Xcode Command Line Tools installed.
+#
+# USAGE:
+#   ./scripts/remote-build-display-control.sh              # uses default Mac (laptop 01)
+#   ./scripts/remote-build-display-control.sh 192.168.32.102
+#
+# The default IP is laptop 01 — the designated build Mac.
+# Change DEFAULT_IP below if Xcode moves to a different laptop.
+#
+# SSH key must already be installed on the target:
+#   ssh-copy-id "speaker ready"@192.168.32.101
+
+set -eo pipefail
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+REPO_ROOT="$(cd "$SCRIPT_DIR/.." && pwd)"
+SRC="$SCRIPT_DIR/display_control.m"
+OUT_BIN="$REPO_ROOT/resources/bin/display_control"
+
+SSH_USER="speaker ready"
+DEFAULT_IP="192.168.32.101"
+IP="${1:-$DEFAULT_IP}"
+
+REMOTE_TMP="/tmp/ae_display_control_build"
+
+echo "═══════════════════════════════════════════════"
+echo "  Remote build: display_control"
+echo "  Build Mac: $SSH_USER @ $IP"
+echo "═══════════════════════════════════════════════"
+
+# ── Step 1: Copy source to remote ────────────────────────────────────────────
+
+echo ""
+echo "Step 1/4 — Copying source to $IP..."
+ssh "$SSH_USER@$IP" "mkdir -p $REMOTE_TMP"
+scp "$SRC" "$SSH_USER@$IP:$REMOTE_TMP/display_control.m"
+
+# ── Step 2: Build universal binary on remote ──────────────────────────────────
+
+echo ""
+echo "Step 2/4 — Building on $IP..."
+ssh "$SSH_USER@$IP" bash << 'ENDSSH'
+set -e
+REMOTE_TMP="/tmp/ae_display_control_build"
+SRC="$REMOTE_TMP/display_control.m"
+TMP_X86="$REMOTE_TMP/display_control_x86_64"
+TMP_ARM="$REMOTE_TMP/display_control_arm64"
+OUT="$REMOTE_TMP/display_control"
+
+echo "  Compiling x86_64..."
+clang -arch x86_64 -framework Cocoa -framework Carbon -o "$TMP_X86" "$SRC"
+
+echo "  Compiling arm64..."
+clang -arch arm64 -framework Cocoa -framework Carbon -o "$TMP_ARM" "$SRC"
+
+echo "  Linking universal binary..."
+lipo -create -output "$OUT" "$TMP_X86" "$TMP_ARM"
+rm "$TMP_X86" "$TMP_ARM"
+chmod +x "$OUT"
+
+echo "  Archs: $(lipo -archs "$OUT")"
+ENDSSH
+
+# ── Step 3: Pull binary back ──────────────────────────────────────────────────
+
+echo ""
+echo "Step 3/4 — Pulling binary to resources/bin/..."
+mkdir -p "$(dirname "$OUT_BIN")"
+scp "$SSH_USER@$IP:$REMOTE_TMP/display_control" "$OUT_BIN"
+chmod +x "$OUT_BIN"
+
+# ── Step 4: Clean up remote ───────────────────────────────────────────────────
+
+echo ""
+echo "Step 4/4 — Cleaning up remote..."
+ssh "$SSH_USER@$IP" "rm -rf $REMOTE_TMP"
+
+# ── Done ──────────────────────────────────────────────────────────────────────
+
+echo ""
+echo "═══════════════════════════════════════════════"
+echo "  Built: $OUT_BIN"
+file "$OUT_BIN"
+echo ""
+echo "  If both archs shown above, you're good:"
+echo "    git add resources/bin/display_control"
+echo "    git commit -m \"build: update display_control binary (universal)\""
+echo "═══════════════════════════════════════════════"