input: one-packet pointer moves, uinput-only injection, fire-and-forget

- Pointer motion is now a single event carrying both coordinates (MOVE_ABS /
  MOVE_REL with x,y) rather than one event per axis; the adapter actuates both
  axes in a single batch. The per-axis ABS/REL kinds are removed.
- Input injection is uinput-only: the driver selection and the optional
  guest-side passthrough drop out of the adapter config (the driver is the
  driver's concern). A QMP path is still carried for the unchanged service
  power/lifecycle path.
- A per-event fire-and-forget flag lets a control inject input without an
  actuation acknowledgement, for high-rate streams; without it the addressed
  ACT_ACK is emitted as before. Service commands always acknowledge.

The neutral input payload gains x/y/flags, still within the inline event body.
Capability, lease and source gates are unchanged.

CMakeLists.txt

@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.16)
-project(vmsig C)
+project(vmsig VERSION 0.2.0 C)
 
 set(CMAKE_C_STANDARD 17)
 set(CMAKE_C_STANDARD_REQUIRED ON)