Fix ZeroGPU nested @spaces.GPU causing CUDA failure 35

Remove @spaces.GPU from internal AppState methods (run_preprocess,
run_svs, run_svs_from_paths) since they are already called from
Gradio-facing functions that hold the GPU context. Also enable
share=True in app.py launch.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -25,4 +25,5 @@ if __name__ == "__main__":
     page.launch(
         server_name="0.0.0.0",
         server_port=int(os.environ.get("PORT", "7860")),
+        share=True,
     )

webui.py

@@ -170,7 +170,6 @@ class AppState:
         )
         self.phoneset_path = "soulxsinger/utils/phoneme/phone_set.json"
 
-    @spaces.GPU
     def run_preprocess(
         self,
         prompt_path: Path,
@@ -200,7 +199,6 @@ class AppState:
         except Exception as e:
             return False, f"preprocess failed: {e}"
 
-    @spaces.GPU
     def run_svs(
         self,
         control: str,
@@ -237,7 +235,6 @@ class AppState:
         except Exception as e:
             return False, f"svs inference failed: {e}", None, prompt_meta_path, target_meta_path
 
-    @spaces.GPU
     def run_svs_from_paths(
         self,
         prompt_wav_path: str,