[client] wayland: constrain pointer only during capture

Remove the persistent confined-pointer workaround that emulated cursor
warping on Wayland. Normal pointer motion now uses absolute input only.

Create relative and locked pointer objects only during capture. Preserve
the request across pointer capability changes, and suppress relative
events until the compositor confirms the lock.

On uncapture, publish the current absolute position instead of trying to
warp the host cursor.

doc/usage.rst

@@ -432,8 +432,6 @@ All command line options
   +-----------------------+-------+-------+-------------------------+
   | Long                  | Short | Value | Description             |
   +=======================+=======+=======+=========================+
-  | wayland:warpSupport   |       | yes   | Enable cursor warping   |
-  +-----------------------+-------+-------+-------------------------+
   | wayland:fractionScale |       | yes   | Enable fractional scale |
   +-----------------------+-------+-------+-------------------------+