Add live scan progress and graceful Ctrl-C handling

lib/scanner.py

@@ -29,14 +29,19 @@ def masscan_sweep(cidrs: list[str], ports: list[int], rate: int, output_dir: Pat
         f"--ports={port_str}",
         "-iL", str(cidr_file),
         "-oJ", str(out_file),
-        "--output-format", "json",
         "--wait", "3",
     ]
 
     try:
-        subprocess.run(cmd, capture_output=True, timeout=3600)
+        proc = subprocess.Popen(cmd, stderr=subprocess.DEVNULL)
+        proc.wait(timeout=3600)
     except subprocess.TimeoutExpired:
-        pass
+        proc.kill()
+        proc.wait()
+    except KeyboardInterrupt:
+        proc.kill()
+        proc.wait()
+        raise
     except FileNotFoundError:
         raise RuntimeError("masscan not found — install it first")