Add egui_inspection protocol and plugin (#8234)

Introduces live inspection for running egui apps over a small TCP
request/response protocol, plus the `egui::Plugin` that serves it.

This is the minimal surface to get the egui mcp in, we may want to
extend this in the future to add support for the inspection gui.

---------

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

crates/eframe/src/native/glow_integration.rs

@@ -299,6 +299,9 @@ impl<'app> GlowWinitApp<'app> {
         let app_creator = std::mem::take(&mut self.app_creator)
             .expect("Single-use AppCreator has unexpectedly already been taken");
 
+        #[cfg(all(not(feature = "inspection"), not(target_arch = "wasm32")))]
+        crate::maybe_attach_inspection_plugin(&integration.egui_ctx, Some(self.app_name.clone()));
+
         let app: Box<dyn 'app + App> = {
             // Use latest raw_window_handle for eframe compatibility
             use raw_window_handle::{HasDisplayHandle as _, HasWindowHandle as _};