GoFileEmpty: no retries for content that exists but is empty; add tools/debug_gofile.py for raw content-API inspection

dlp.py

@@ -157,7 +157,7 @@ def run_gofile(
             try:
                 files_spec = client.list_files(f.url)
                 if not files_spec:
-                    raise dlph_gofile.GoFileError("no files found under URL")
+                    raise dlph_gofile.GoFileEmpty("content exists but contains no files")
                 files: list[dict] = []
                 for relpath, name, link in files_spec:
                     dest = Path(args.out_dir) / "downloads" / "gofile" / relpath / name
@@ -182,6 +182,11 @@ def run_gofile(
                 log.error("DEAD LINK %s: %s", f.url, exc)
                 state.mark(f.url, status="failed", error=str(exc), files=[])
                 break
+            except dlph_gofile.GoFileEmpty as exc:
+                # Emptied content is stable - no retry
+                log.error("EMPTY CONTENT %s: %s", f.url, exc)
+                state.mark(f.url, status="failed", error=str(exc), files=[])
+                break
             except dlph_gofile.GoFileAuthError as exc:
                 # Token may have died mid-run (rate limit); re-auth once per attempt
                 log.warning("Auth error for %s: %s - re-authenticating", f.url, exc)