build: add display_control binary (universal x86_64+arm64)

scp's own user@host:path parser splits on the space in 'speaker ready'
even when the shell argument is quoted. ssh already handles it correctly.
Upload: ssh cat < file; Download: ssh cat > file.

README.md

@@ -296,7 +296,7 @@ to change.
 | `window_control({action, value?})` | Electron window: maximize, minimize, restore, close, fullscreen, kiosk, devtools, reload. |
 | `set_wallpaper({path?, url?, url_external?, display?, api_key?, account_id?})` | Sets desktop wallpaper. Accepts a local `path` or downloads from `url` (cached to `~/Library/Caches/OSIT/wallpaper/`). `url_external` sets a separate image on the projector/second display. `display`: `'all'` (default) \| `'primary'` \| `'external'`. macOS only in production; Linux returns a dev-mode preview payload without applying. |
 | `power_control({action})` | Shutdown, reboot, or sleep. macOS + Linux. Requires sudo for shutdown/reboot. |
-| `set_display_layout({mode, configStr?})` | Mirror/extend displays via bundled `displayplacer` binary. macOS only. Auto-detects connected displays via `displayplacer list` when no `configStr` is given — no manual config needed. `configStr` is an optional manual override (the full `displayplacer` config string) stored in `event_device.data_json` if per-device tuning is needed. |
+| `set_display_layout({mode, configStr?})` | Mirror/extend displays. macOS only. **Primary path:** bundled `display_control` binary (native CoreGraphics, no Homebrew). **Fallback:** `displayplacer` — used when `display_control` binary is absent, or when a `configStr` override is set. `configStr` is an optional manual override (full `displayplacer` config string) stored in `event_device.data_json` for per-device tuning. Build `display_control` once via `scripts/build-display-control.sh` on a Mac and commit `resources/bin/display_control`. |
 | `manage_recording({action, options?})` | Screen recording via bundled `aperture` binary. macOS only. |
 | `update_app(args)` | **Stub.** Downloads update package but does not install. Not functional. |
 | `list_tools()` | Returns a self-describing manifest of all available bridge functions. |
@@ -352,6 +352,57 @@ See `documentation/PROJECT__AE_Events_Launcher_Native_integration.md` Section 8
 - **Handlers:** OS-level logic in `src/main/shell_handlers.ts`, `src/main/file_handlers.ts`, and `src/main/system_handlers.ts`.
 - **Types:** Shared TypeScript interfaces in `src/shared/types.ts`.
 
+### One-Time: Build the `display_control` Binary (macOS)
+
+The `display_control` binary provides native CoreGraphics display mirror/extend without any Homebrew dependency. It must be compiled on a Mac (Xcode CLT required) and committed to the repo so it is bundled into every packaged app. Produces a universal binary (x86_64 + arm64) that runs on both Intel and Apple Silicon Macs.
+
+Rebuild only if `scripts/display_control.m` changes.
+
+#### Option A — From the Linux workstation (preferred)
+
+Laptop 01 (`192.168.32.101`) is the designated build Mac — Xcode CLT is installed there.
+The remote build script copies the source over SSH, compiles on that Mac, and pulls the binary back.
+
+```bash
+# From the repo root on the workstation:
+./scripts/remote-build-display-control.sh
+
+# Override the build Mac IP if needed:
+./scripts/remote-build-display-control.sh 192.168.32.102
+```
+
+The script prints `file resources/bin/display_control` at the end. Confirm both arches appear:
+```
+resources/bin/display_control: Mach-O universal binary with 2 architectures: [x86_64] [arm64]
+```
+
+Then commit:
+```bash
+git add resources/bin/display_control
+git commit -m "build: update display_control binary (universal)"
+```
+
+#### Option B — Directly on a Mac
+
+If you have repo access on the Mac itself (Xcode CLT required — `xcode-select --install`):
+
+```bash
+./scripts/build-display-control.sh
+# Expected last output line: x86_64 arm64
+
+# Test with a second display connected:
+./resources/bin/display_control status
+./resources/bin/display_control extend
+./resources/bin/display_control mirror
+
+git add resources/bin/display_control
+git commit -m "build: update display_control binary (universal)"
+```
+
+Once committed, `brew install displayplacer` is no longer required on any venue Mac. The `displayplacer` fallback remains in the handler only for `configStr` per-device overrides.
+
+---
+
 ### Build Requirements (System Dependencies)
 
 `bsdtar` (libarchive) must be present on the build host. It is used by the `postinstall` patch

scripts/build-display-control.sh

@@ -24,13 +24,26 @@ fi
 
 mkdir -p "$OUT_DIR"
 
-echo "Building display_control..."
-clang -framework Cocoa -framework Carbon \
-    -o "$OUT_BIN" "$SRC"
+TMP_X86="$OUT_DIR/display_control_x86_64"
+TMP_ARM="$OUT_DIR/display_control_arm64"
+
+echo "Building display_control (x86_64)..."
+clang -arch x86_64 -framework Cocoa -framework Carbon \
+    -o "$TMP_X86" "$SRC"
+
+echo "Building display_control (arm64)..."
+clang -arch arm64 -framework Cocoa -framework Carbon \
+    -o "$TMP_ARM" "$SRC"
+
+echo "Linking universal binary..."
+lipo -create -output "$OUT_BIN" "$TMP_X86" "$TMP_ARM"
+rm "$TMP_X86" "$TMP_ARM"
 
 chmod +x "$OUT_BIN"
 
-echo "Built: $OUT_BIN"
+echo ""
+echo "Built universal binary: $OUT_BIN"
+lipo -archs "$OUT_BIN"
 echo ""
 echo "Test it:"
 echo "  $OUT_BIN status"

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 $REMOTE_TMP"
+ssh "$SSH_USER@$IP" "cat > $REMOTE_TMP/display_control.m" < "$SRC"
+
+# ── 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")"
+ssh "$SSH_USER@$IP" "cat $REMOTE_TMP/display_control" > "$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 "═══════════════════════════════════════════════"

src/main/system_handlers.ts

@@ -335,8 +335,10 @@ export function registerSystemHandlers() {
       : path.join(__dirname, '../../resources/bin/display_control');
 
     if (fs.existsSync(dc_bin) && !configStr) {
-      const dc_cmd = mode === 'mirror' ? 'mirror' : 'extend';
-      return await runExec(`"${dc_bin}" ${dc_cmd}`);
+      if (mode !== 'mirror' && mode !== 'extend') {
+        return { success: false, error: `Unsupported display mode: ${mode}` };
+      }
+      return await runExec(`"${dc_bin}" ${mode}`);
     }
 
     // Fallback: displayplacer — required when display_control binary is not built yet,