fix(pf-vdisplay,pf-win-display): v4 trait surface on the extracted driver.rs + cross-crate visibility

The W-refactor extracted VdisplayDriver into manager/driver.rs (the merge
resolution assumed it deleted) — carry the v4 changes there: open() returns the
driver's protocol version, update_modes() default-errs to the re-arrival
fallback. wait_target_departed goes pub for the manager's cross-crate call.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

crates/pf-win-display/src/win_display.rs

@@ -375,7 +375,7 @@ pub(crate) fn wait_mode_advertised(
 ///
 /// # Safety
 /// Runs the CCD query FFI; call under the manager `state` lock like the callers it serves.
-pub(crate) unsafe fn wait_target_departed(target_id: u32, ceiling: std::time::Duration) -> bool {
+pub unsafe fn wait_target_departed(target_id: u32, ceiling: std::time::Duration) -> bool {
     let deadline = std::time::Instant::now() + ceiling;
     let mut absent_streak = 0u32;
     loop {