feat(whisper): register set_abort symbol in the purego loader

Adds the Go-side binding for the new C export so the next commit can
call CppSetAbort(1) from a watcher goroutine on ctx.Done().

Assisted-by: Claude:claude-haiku-4-5
Signed-off-by: Ettore Di Giacinto <mudler@localai.io>

backend/go/whisper/gowhisper.go

@@ -25,6 +25,7 @@ var (
 	CppNTokens                   func(i int) int
 	CppGetTokenID                func(i int, j int) int
 	CppGetSegmentSpeakerTurnNext func(i int) bool
+	CppSetAbort                  func(v int)
 )
 
 type Whisper struct {

backend/go/whisper/main.go

@@ -41,6 +41,7 @@ func main() {
 		{&CppNTokens, "n_tokens"},
 		{&CppGetTokenID, "get_token_id"},
 		{&CppGetSegmentSpeakerTurnNext, "get_segment_speaker_turn_next"},
+		{&CppSetAbort, "set_abort"},
 	}
 
 	for _, lf := range libFuncs {