Move controller-poll info from Injection to Controllers panel

The per-slot XInput poll rates and the "game reading controller" summary
describe the controller, not the injection mechanism, so move them to the
Controllers panel (renamed from debug_overlay -> ControllersPanel, now a class
that owns the poll-rate sampling). The panel now shows both directions: the
guest pads the host receives from RPT, and what the injected game reads back.

The Injection panel keeps the hook attach state, focus spoof, focus-API
counts, and input-path diagnostics, and points to the Controllers panel for
poll rates.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

host/src/controllers_panel.hpp

@@ -0,0 +1,31 @@
+// Controllers panel: the controller view of the pipeline. Shows what the host
+// receives from Remote Play Together (the guest pads, via the input backend) and
+// what the injected game actually reads back (per-slot XInput poll counts from the
+// hook). This is how we verify RPT routes a guest's gamepad in and the game polls
+// it out. The per-axis breakdown and per-slot poll table are debug-only.
+#pragma once
+
+#include <cstdint>
+
+#include "coop/protocol.hpp"
+#include "input/input_source.hpp"
+#include "ipc/ipc_server.hpp"
+
+namespace coop
+{
+
+class ControllersPanel
+{
+public:
+	// `status` is the hook's back-channel (per-slot poll counters); `debug_details`
+	// reveals the raw axis values and the per-slot poll-rate table.
+	void draw(const InputSource& input, const HookStatusView& status, bool debug_details);
+
+private:
+	// Sampled to turn the hook's cumulative per-slot counters into poll rates.
+	unsigned long long last_state_count_[kMaxPads] = {};
+	double state_rate_[kMaxPads] = {};
+	double last_sample_time_ = 0.0;
+};
+
+} // namespace coop