Keep Wine accessibility helpers on the reader's session bus

A Wine application can inherit a different D-Bus session address from the
running Cthulhu instance. The helper manager previously copied that address
from the application's environment, redirecting accessibility requests to
a bus where the supervising reader was unavailable. This left foobar2000
and its Preferences dialog silent despite working native control support.

Retain the reader's inherited DBUS_SESSION_BUS_ADDRESS when launching a
helper. Continue taking the application's display, runtime directory,
Wine prefix and loader so hooks still attach to the correct Wine session.
The manager remains responsible for helper startup and shutdown.

Extend the existing manager lifecycle regression to supply conflicting
application and reader bus addresses. Assert that the helper receives the
reader's bus, the application's display, the expected prefix and the
managed-helper marker, while retaining the shutdown checks. The regression
failed against the original implementation before the fix.

Validation:
- GOPROXY=off go test ./internal/wine -count=1
- GOPROXY=off go test -race ./internal/wine -count=1
- GOPROXY=off go vet ./internal/wine
- Built and installed the reader; configuration validation passed.
- After reload, both the default-prefix and Bard helpers used the reader's
  bus. Foobar2000 Preferences opened on workspace 3 without settings changes.
- The user subsequently confirmed that the installed changes look good.

internal/wine/manager.go

@@ -188,7 +188,10 @@ func (manager *Manager) launch(child *process, source prefix, now time.Time) err
 	cmd.WaitDelay = 200 * time.Millisecond
 	cmd.SysProcAttr = &syscall.SysProcAttr{Setsid: true}
 	environment := os.Environ()
-	for _, key := range []string{"DISPLAY", "WAYLAND_DISPLAY", "XDG_RUNTIME_DIR", "DBUS_SESSION_BUS_ADDRESS"} {
+	// Hooks need the application's display, but D-Bus requests go to this
+	// reader's session. Applications launched from another session bus must
+	// not redirect the helper away from the service supervising it.
+	for _, key := range []string{"DISPLAY", "WAYLAND_DISPLAY", "XDG_RUNTIME_DIR"} {
 		if value := source.environment[key]; value != "" {
 			environment = append(environment, key+"="+value)
 		}

internal/wine/manager_test.go

@@ -219,13 +219,14 @@ func TestManagerLaunchesAndStopsHelperForActivePrefix(t *testing.T) {
 	if err := os.WriteFile(filepath.Join(proc, "cmdline"), []byte("application.exe\x00"), 0600); err != nil {
 		t.Fatal(err)
 	}
-	if err := os.WriteFile(filepath.Join(proc, "environ"), []byte("WINEPREFIX="+prefixPath+"\x00WINELOADER="+loader+"\x00"), 0600); err != nil {
+	if err := os.WriteFile(filepath.Join(proc, "environ"), []byte("WINEPREFIX="+prefixPath+"\x00WINELOADER="+loader+"\x00DBUS_SESSION_BUS_ADDRESS=unix:path=/application-bus\x00DISPLAY=:7\x00"), 0600); err != nil {
 		t.Fatal(err)
 	}
 	output := filepath.Join(root, "helper-output")
 	t.Setenv("CTHULHU_TEST_WINE_OUTPUT", output)
+	t.Setenv("DBUS_SESSION_BUS_ADDRESS", "unix:path=/reader-bus")
 	helper := filepath.Join(root, "helper")
-	script := "#!/bin/sh\nprintf '%s\\n' \"$WINEPREFIX\" \"$CTHULHU_WINE_ACCESS_MANAGED\" > \"$CTHULHU_TEST_WINE_OUTPUT\"\nexec sleep 30\n"
+	script := "#!/bin/sh\nprintf '%s\\n' \"$WINEPREFIX\" \"$CTHULHU_WINE_ACCESS_MANAGED\" \"$DBUS_SESSION_BUS_ADDRESS\" \"$DISPLAY\" > \"$CTHULHU_TEST_WINE_OUTPUT\"\nexec sleep 30\n"
 	if err := os.WriteFile(helper, []byte(script), 0700); err != nil {
 		t.Fatal(err)
 	}
@@ -243,7 +244,7 @@ func TestManagerLaunchesAndStopsHelperForActivePrefix(t *testing.T) {
 		}
 		time.Sleep(10 * time.Millisecond)
 	}
-	if string(contents) != prefixPath+"\n1\n" {
+	if string(contents) != prefixPath+"\n1\nunix:path=/reader-bus\n:7\n" {
 		t.Fatalf("helper environment = %q", contents)
 	}
 	stopCtx, cancel := context.WithTimeout(context.Background(), time.Second)