fix: improve error handling and refactor app initialization process in HTTP handler

Co-authored-by: Copilot <copilot@github.com>

panel-api.py

@@ -548,6 +548,7 @@ class Handler(BaseHTTPRequestHandler):
                 self._json(400, {"ok": False, "error": "invalid source_type"})
                 return
 
+            try:
                 result = run_panelctl(["init", name, domain, port, auth])
                 if not result["ok"]:
                     self._json(400, result)
@@ -654,6 +655,9 @@ class Handler(BaseHTTPRequestHandler):
                         return
 
                 self._json(200, {"ok": True, "code": 0, "stdout": "initialized successfully"})
+            except Exception as exc:
+                run_panelctl(["remove", name])
+                self._json(500, {"ok": False, "error": f"init failed: {exc}"})
             return
 
         if len(parts) >= 3 and parts[0] == "apps":