chore(startup): name the WebView2 runtime and mark every milestone

His startup.log stops after 'data dir ok', which rules out the two faults
already covered and leaves the window creation itself — where a missing
WebView2 runtime lands, sometimes as a silent exit rather than an error
anyone can print.

So the runtime's version is read from where it registers itself (both
hives, and the 32-bit view where a per-machine install usually lands) and
written BEFORE the window is attempted: 'WebView2: not found' answers the
whole question in one line. Breadcrumbs now also mark entering wails.Run,
reaching OnStartup, and the window painting — which places any launch
that produces nothing between two known points.

main.go

@@ -114,6 +114,16 @@ func main() {
 		cleanupOldUpdateBinary()
 	}
 
+	// The WebView2 runtime, named before the window is attempted. Its absence is
+	// the classic silent failure — the process starts, the browser environment
+	// cannot be created, and on some machines that ends the launch without an
+	// error anyone can see.
+	if v := webView2Version(); v != "" {
+		bootLog("WebView2 runtime: %s", v)
+	} else {
+		bootLog("WebView2 runtime: NOT FOUND — install Microsoft Edge WebView2 Runtime")
+	}
+
 	// Create an instance of the app structure
 	app := NewApp()
 	app.startupProfile = profileArg(os.Args[1:])
@@ -135,6 +145,7 @@ func main() {
 	}
 
 	// Create application with options
+	bootLog("entering wails.Run (window %dx%d, state %v)", width, height, startState)
 	err := wails.Run(&options.App{
 		Title:            "OpsLog",
 		Width:            width,
@@ -168,6 +179,7 @@ func main() {
 		},
 	})
 
+	bootLog("wails.Run returned")
 	if err != nil {
 		// The last thing that can fail before a window exists, and the most
 		// opaque of them: a missing WebView2 runtime lands here. println goes