add linuxJoystick input module (#10970)

* add linuxJoystick input module

* close epollfd to avoid leaks

src/input/LinuxJoystick.h

@@ -0,0 +1,51 @@
+#pragma once
+// Linux evdev gamepad/joystick input. Only compiled on Linux portduino targets;
+// macOS / non-Linux builds have no <linux/input.h> or epoll. Unlike LinuxInput
+// (keyboard, EV_KEY only) this decodes the D-pad from EV_ABS axes as well.
+#if ARCH_PORTDUINO && defined(__linux__)
+#include "InputBroker.h"
+#include "concurrency/OSThread.h"
+#include <linux/input.h>
+#include <map>
+#include <stdint.h>
+#include <sys/epoll.h>
+
+#define JOY_MAX_EVENTS 10
+
+// Default button map when config.yaml has no [Input] JoystickButtons override.
+// Codes confirmed by evdev capture on a 0079:0011 "USB Gamepad".
+#define JOY_BTN_A BTN_THUMB  // 0x121 -> INPUT_BROKER_SELECT
+#define JOY_BTN_B BTN_THUMB2 // 0x122 -> INPUT_BROKER_CANCEL
+#define JOY_AXIS_CENTER 127  // D-pad resting value
+#define JOY_AXIS_LOW 64      // below this -> "min" edge (0)
+#define JOY_AXIS_HIGH 192    // above this -> "max" edge (255)
+
+class LinuxJoystick : public Observable<const InputEvent *>, public concurrency::OSThread
+{
+  public:
+    explicit LinuxJoystick(const char *name);
+    void init();   // Registers this source with the InputBroker
+    void deInit(); // Strictly for cleanly "rebooting" the binary on native
+
+  protected:
+    virtual int32_t runOnce() override;
+
+  private:
+    const char *_originName;
+    bool firstTime = true;
+
+    // evdev button code -> broker event, built from config (or defaults) in init().
+    std::map<int, input_broker_event> buttonMap;
+
+    struct epoll_event events[JOY_MAX_EVENTS];
+    struct epoll_event ev;
+    int fd = -1;
+    int epollfd = -1;
+
+    // Latch the last emitted axis position so a held direction fires exactly
+    // once (on the transition away from center), not a continuous stream.
+    int lastX = JOY_AXIS_CENTER;
+    int lastY = JOY_AXIS_CENTER;
+};
+extern LinuxJoystick *aLinuxJoystick;
+#endif