fix: align process_run_status/exit signatures to I32 (int-type-split)

Aligns `process_run_status` and `exit` return/parameter types from `Int`
to `I32`, following the spore int-type-split change (Ty::Int → sized variants).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: zrr1999

src/basic_cli/cmd.sp

@@ -7,7 +7,7 @@
 pub foreign fn process_run(cmd: Str, args: List[Str]) -> Str ! ExecError uses [Spawn]
 
 /// Run a command and return its exit code.
-pub foreign fn process_run_status(cmd: Str, args: List[Str]) -> Int ! ExecError uses [Spawn]
+pub foreign fn process_run_status(cmd: Str, args: List[Str]) -> I32 ! ExecError uses [Spawn]
 
 /// Exit the current process with the provided status code.
-pub foreign fn exit(code: Int) -> Never uses [Exit]
+pub foreign fn exit(code: I32) -> Never uses [Exit]