fix(vt100): treat OSError on add_reader as EOFError (macOS kqueue)

`Vt100Input._attached_input` already raises `EOFError` when
`loop.add_reader(fd, ...)` fails with `PermissionError`, which is what
Linux's `EPollSelector` raises when stdin points at /dev/null.

macOS's `KqueueSelector` does not raise `PermissionError` for the same
class of "unpollable stdin" cases — it raises `OSError [Errno 22]
Invalid argument` (from `kqueue.control()`). This currently propagates
all the way up out of `Application.run()` and crashes any consumer that
expected the existing `EOFError` contract.

Reproducer (macOS):

    python -c "from prompt_toolkit import prompt; prompt('> ')" \
        0< /dev/null

Or any wrapper that launches a prompt_toolkit app with a non-TTY stdin
on macOS — e.g. spawned from another agent process that has reassigned
fd 0.

Treat both `PermissionError` and `OSError` from `add_reader` as
end-of-input and raise `EOFError`, so callers see the same exception
regardless of which selector backend asyncio picked.

Author: mads

src/prompt_toolkit/input/vt100.py

@@ -167,12 +167,14 @@ def callback_wrapper() -> None:
 
     try:
         loop.add_reader(fd, callback_wrapper)
-    except PermissionError:
+    except (PermissionError, OSError):
         # For `EPollSelector`, adding /dev/null to the event loop will raise
         # `PermissionError` (that doesn't happen for `SelectSelector`
-        # apparently). Whenever we get a `PermissionError`, we can raise
-        # `EOFError`, because there's not more to be read anyway. `EOFError` is
-        # an exception that people expect in
+        # apparently). On macOS `KqueueSelector`, an unpollable stdin fd
+        # (e.g. detached parent, /dev/null, or otherwise non-TTY) raises
+        # `OSError [Errno 22] Invalid argument` instead. Both mean "nothing
+        # more to read here", so we surface them as `EOFError`, which is an
+        # exception people expect in
         # `prompt_toolkit.application.Application.run()`.
         # To reproduce, do: `ptpython 0< /dev/null 1< /dev/null`
         raise EOFError