refactor(Wind): Improve extension host debugging observability

Enhance the extension host handshake and RPC message handling in Preload with more granular performance marks and debug logging.

Changes:
- Split single `handshake-complete` mark into three specific marks: `init-data-received`, `initialized-sent`, and `ready-sent`
- Add debug logging that outputs init data byte size and text preview (first 200 chars) for diagnosing initialization issues
- Rename message performance marks from `message:N` to `rpc:N` for clarity
- Log the first 5 RPC messages with byte size and preview for debugging protocol issues

These improvements enable better visibility into the extension host initialization flow and help diagnose communication problems between Wind and Cocoon.

Author: NikolaRHristov

Source/Preload.ts

@@ -239,7 +239,16 @@ const ipcMessagePort = {
 				if (Length > 1) {
 					HandshakeComplete = true;
 					try {
-						performance.mark("land:exthost:handshake-complete");
+						performance.mark("land:exthost:handshake:init-data-received", {
+							detail: { bytes: Length },
+						});
+					} catch {}
+
+					// Log init data summary for debugging
+					try {
+						const Bytes = Data instanceof Uint8Array ? Data : new Uint8Array(Data);
+						const Text = new TextDecoder().decode(Bytes.slice(0, 500));
+						console.warn("[Extension Host] Init data received:", Length, "bytes, preview:", Text.slice(0, 200));
 					} catch {}
 
 					// Forward init data to Mountain for Cocoon
@@ -251,18 +260,34 @@ const ipcMessagePort = {
 
 					// MessageType.Initialized → byte 1
 					port1.postMessage(new Uint8Array([1]));
+
+					try {
+						performance.mark("land:exthost:handshake:initialized-sent");
+					} catch {}
+					console.warn("[Extension Host] Handshake complete — Initialized sent");
+				} else {
+					console.warn("[Extension Host] Handshake: ignoring control byte", Length > 0 ? new Uint8Array(Data instanceof ArrayBuffer ? Data : Data)[0] : "empty");
 				}
 				return;
 			}
 
-			// Post-handshake: forward extension host protocol messages
+			// Post-handshake: forward extension host protocol messages (RPC)
 			MessageCount++;
 			try {
-				performance.mark(`land:exthost:message:${MessageCount}`, {
+				performance.mark(`land:exthost:rpc:${MessageCount}`, {
 					detail: { bytes: Length },
 				});
 			} catch {}
 
+			if (MessageCount <= 5) {
+				// Log first few RPC messages for debugging
+				try {
+					const Bytes = Data instanceof Uint8Array ? Data : new Uint8Array(Data);
+					const Preview = new TextDecoder().decode(Bytes.slice(0, 200));
+					console.warn(`[Extension Host] RPC #${MessageCount}:`, Length, "bytes, preview:", Preview.slice(0, 150));
+				} catch {}
+			}
+
 			if (Length > 0) {
 				ForwardToMountain(
 					Data instanceof Uint8Array ? Data : new Uint8Array(Data),
@@ -287,6 +312,10 @@ const ipcMessagePort = {
 		// MessageType.Ready → byte 2
 		setTimeout(() => {
 			port1.postMessage(new Uint8Array([2]));
+			try {
+				performance.mark("land:exthost:handshake:ready-sent");
+			} catch {}
+			console.warn("[Extension Host] Ready sent on MessagePort, waiting for init data...");
 		}, 50);
 	},
 };