Add examples to App command dialog

Show platform-specific examples when adding or editing an App command:
- Windows: notepad.exe, paths with quotes
- Linux: firefox with URL
- macOS: open -a Safari

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

gui/macro_editor.py

@@ -243,7 +243,15 @@ class CommandBuilder(QWidget):
 
         elif cmd_type == "app":
             from PySide6.QtWidgets import QInputDialog
-            cmd, ok = QInputDialog.getText(self, "App Command", "Enter application command:")
+            cmd, ok = QInputDialog.getText(
+                self, "App Command",
+                "Enter application command:\n\n"
+                "Examples:\n"
+                "  Windows: notepad.exe\n"
+                "  Windows: \"C:\\Program Files\\App\\app.exe\"\n"
+                "  Linux: firefox https://example.com\n"
+                "  macOS: open -a Safari"
+            )
             if not ok or not cmd:
                 return
             command["command"] = cmd
@@ -314,7 +322,13 @@ class CommandBuilder(QWidget):
 
         elif cmd_type == "app":
             text, ok = QInputDialog.getText(
-                self, "Edit App", "Enter application command:",
+                self, "Edit App",
+                "Enter application command:\n\n"
+                "Examples:\n"
+                "  Windows: notepad.exe\n"
+                "  Windows: \"C:\\Program Files\\App\\app.exe\"\n"
+                "  Linux: firefox https://example.com\n"
+                "  macOS: open -a Safari",
                 text=cmd.get("command", "")
             )
             if ok and text: