feat(sandbox): implement cross-platform support with Windows fallback

- Add conditional compilation for Unix-specific gaol sandbox functionality
- Implement Windows-compatible SandboxExecutor with no-op sandboxing
- Update ProfileBuilder to handle both Unix and Windows platforms
- Add platform-specific dependency declaration for gaol crate
- Modify agent and claude commands to use appropriate sandbox implementation
- Update test modules with conditional compilation for Unix-only tests
- Ensure graceful degradation on Windows with logging warnings

This change enables the application to build and run on Windows while
maintaining full sandbox security on Unix-like systems.

src-tauri/src/commands/claude.rs

@@ -1021,7 +1021,14 @@ fn create_sandboxed_claude_command(app: &AppHandle, project_path: &str) -> Resul
                             
                             // Use the helper function to create sandboxed command
                             let claude_path = find_claude_binary(app)?;
-                            Ok(create_sandboxed_command(&claude_path, &[], &project_path_buf, profile, project_path_buf.clone()))
+                            #[cfg(unix)]
+                            return Ok(create_sandboxed_command(&claude_path, &[], &project_path_buf, profile, project_path_buf.clone()));
+                            
+                            #[cfg(not(unix))]
+                            {
+                                log::warn!("Sandboxing not supported on Windows, using regular command");
+                                Ok(create_command_with_env(&claude_path))
+                            }
                         }
                         Err(e) => {
                             log::error!("Failed to build sandbox profile: {}, falling back to non-sandboxed", e);