update SYNC.md — real fix pushed (setAlwaysOnTop + X button working)

SYNC.md

@@ -37,21 +37,22 @@ If a plugin crashes → only Helper dies → Ableton survives → UI shows "Relo
 - ❌ `addDefaultFormats()` (deleted in JUCE 8)
 - ❌ `juce::Thread::setCurrentThreadPriority()` (removed in JUCE 8)
 - ❌ `MSG_NOSIGNAL` (doesn't exist on macOS)
-- ❌ `NSApplicationActivationPolicyAccessory` — BROKE fullscreen window behavior, reverted
-- ❌ `NSWindowCollectionBehavior` changes — didn't fix fullscreen, made it worse, reverted
-- ❌ Window level changes (3→25) — unnecessary, reverted
+- ❌ `NSApplicationActivationPolicyAccessory` — broke fullscreen, reverted
+- ❌ `showAsFloatingPanel()` with objc_msgSend level hacks — broke fullscreen, reverted
+- ❌ `NSWindowCollectionBehavior` changes — didn't help, reverted
+- ❌ Window level 25 (NSStatusWindowLevel) — unnecessary, reverted
 
 ## What's Working
 - ✅ Out-of-process via shared memory + semaphores + Unix socket
 - ✅ Crash-safe — plugins that abort() only kill the helper
-- ✅ Plugin GUI window (close button hides, doesn't quit Helper)
+- ✅ Plugin GUI via `setAlwaysOnTop(true)` — stays in same Space as Ableton (including fullscreen)
+- ✅ X button hides GUI (doesn't quit Helper)
 - ✅ Toggle GUI via button in PluginBridge panel (Open GUI / Close GUI)
 - ✅ Plugin list from filesystem (no binary loading until user selects)
 - ✅ Native pthread priority for audio thread
 
 ## Status
-**Last push:** 2026-05-16 — REVERTED all window policy changes. Back to original working state where GUI opened inside Ableton's Space correctly.
+**Last push:** 2026-05-16 — Fixed fullscreen issue. Root cause: commit 0632681 replaced `setAlwaysOnTop(true)` with objc_msgSend hacks that broke Space behavior. Fix: restored `setAlwaysOnTop(true)` + kept X button fix.
 **Build:** Needs test
-**Test:** Pull, build, load in Ableton (FULLSCREEN) → Open GUI → confirm it opens in same Space as Ableton (like it did before the close-button fix).
-**If it still opens separately:** The problem was introduced by the close-button fix (PluginGuiWindow class). Need to identify what specifically changed. The ONLY difference from original working code should be `closeButtonPressed() { setVisible(false); }` instead of whatever it was before.
-**Next:** Once GUI confirmed working → Sprint 3 (MCP param control)
+**Test:** Pull, build, Ableton fullscreen → Open GUI → should open in same Space. X button should hide (not quit).
+**Next:** Sprint 3 — MCP param control from Claude Code (curl tests)