feat: AR Display Manager — multi-monitor floating app switcher

Adds the AR Display Manager daemon (Task #9):

- display_manager/ package with 8 modules:
  - app_registry.py   : static metadata for the 4 bridge apps
  - config.py         : JSON-persisted config + per-screen layout store
  - win32_utils.py    : ctypes wrappers (EnumWindows, SetWindowPos, ShowWindow)
  - process_manager.py: launch + track app processes, HWND lookup
  - floating_button.py: always-on-top 52×52 px AR button per monitor
                        with draggable placement + custom-painted popup
  - display_manager.py: orchestrator (QScreens → buttons → app placement
                        + system tray with Settings/Launch/Quit)
  - settings_dialog.py: modal dialog for exe paths, button position,
                        and Windows autostart toggle
  - autostart.py      : HKCU Run registry read/write helpers
- display_manager_main.py at repo root: launcher script
- Studio Overview tab: "Lanzar Display Manager" button
- pyproject.toml: display-manager optional dependency group (PySide6)

Layout persistence: ~/.ar-autopilot/display_manager/layout.json
Config:            ~/.ar-autopilot/display_manager/config.json
Supports up to 4 monitors (2 HDMI native + 2 USB DisplayLink).
Double-click tray icon to toggle button visibility.

AR_electronics — AR-Autopilot Project

arautopilot/studio/main_window.py

@@ -18,9 +18,12 @@ from PySide6.QtCore import Qt
 from PySide6.QtGui import QFont, QPixmap
 from PySide6.QtWidgets import (
     QFrame,
+    QHBoxLayout,
     QLabel,
     QListWidget,
     QMainWindow,
+    QMessageBox,
+    QPushButton,
     QSplitter,
     QStatusBar,
     QTabWidget,
@@ -193,6 +196,30 @@ class StudioMainWindow(QMainWindow):
         guide.setTextFormat(Qt.TextFormat.RichText)
         guide.setWordWrap(True)
         layout.addWidget(guide)
+
+        # AR Display Manager quick launch
+        sep2 = QFrame()
+        sep2.setFrameShape(QFrame.Shape.HLine)
+        sep2.setStyleSheet(f"color:{ACCENT_MID}; margin: 10px 0;")
+        layout.addWidget(sep2)
+
+        dm_row = QHBoxLayout()
+        dm_label = QLabel(
+            f"<b style='color:{ACCENT_MID}'>🖥  AR Display Manager</b><br/>"
+            f"<span style='color:{TEXT_MUTED};font-size:11px;'>"
+            "Gestiona cuál app aparece en cada monitor del J6412 "
+            "(hasta 4 pantallas simultáneas).</span>"
+        )
+        dm_label.setTextFormat(Qt.TextFormat.RichText)
+        dm_label.setWordWrap(True)
+        dm_row.addWidget(dm_label, stretch=1)
+
+        dm_btn = QPushButton("Lanzar Display Manager")
+        dm_btn.setMinimumWidth(200)
+        dm_btn.clicked.connect(self._launch_display_manager)
+        dm_row.addWidget(dm_btn)
+        layout.addLayout(dm_row)
+
         layout.addStretch(1)
 
         footer = QLabel(
@@ -204,3 +231,27 @@ class StudioMainWindow(QMainWindow):
         layout.addWidget(footer)
 
         return w
+
+    # ── Display Manager launcher ──────────────────────────────────────────────
+
+    def _launch_display_manager(self) -> None:
+        import subprocess
+        import sys as _sys
+        launcher = REPO_ROOT / "display_manager_main.py"
+        if not launcher.exists():
+            QMessageBox.warning(
+                self,
+                "Not found",
+                f"display_manager_main.py not found at:\n{launcher}",
+            )
+            return
+        try:
+            subprocess.Popen(
+                [_sys.executable, str(launcher)],
+                creationflags=(
+                    subprocess.CREATE_NEW_PROCESS_GROUP
+                    if _sys.platform == "win32" else 0
+                ),
+            )
+        except Exception as exc:
+            QMessageBox.critical(self, "Launch failed", str(exc))