docs: clarify GC no-region parameter and byte/bool P/Invoke boundary comments

Agent-Logs-Url: https://github.com/winnerspiros/osu/sessions/2523e170-1d43-41d8-af53-47db9142dcaa

Co-authored-by: winnerspiros <1675249+winnerspiros@users.noreply.github.com>

Author: Copilot

osu.Android/Native/oboe_bridge.cpp

@@ -841,6 +841,10 @@ OSU_EXPORT void nADPFCloseSession(intptr_t sessionPtr) {
 // giving an additional ~5% clock-frequency boost at the cost of slightly higher
 // power draw — acceptable for an interactive game session.
 // preferEfficiency=0 → prefer performance (disable power-efficiency bias).
+//
+// P/Invoke boundary uses `byte` instead of `bool` because Mono's P/Invoke marshaller
+// does not guarantee a 1-byte ABI for C++ `bool`.  The native side receives a `byte`
+// and converts it via `preferEfficiency != 0` before forwarding to the API's `bool` param.
 OSU_EXPORT void nADPFSetPreferPowerEfficiency(intptr_t sessionPtr, byte preferEfficiency) {
     if (!sessionPtr) return;
 

osu.Android/Performance/AndroidHighPerformanceSessionManager.cs

@@ -122,6 +122,8 @@ private void enterSession()
             {
                 try
                 {
+                    // disallowFullBlockingGC: false — if allocation exceeds the budget,
+                    // the runtime silently reverts to normal GC instead of throwing.
                     noGCRegionActive = GC.TryStartNoGCRegion(NO_GC_REGION_BUDGET_BYTES, disallowFullBlockingGC: false);
                     if (noGCRegionActive)
                         Logger.Log("High performance session: no-GC region started (64 MB budget)");