fix(browser): address Copilot review on /browser connect

Fixes from Copilot's two passes on PR #17238:

* Validate parsed URL once: reject missing host, invalid port, and
  unsupported scheme up front so malformed inputs (e.g. http://:9222
  or http://localhost:abc) don't fall through to a generic 5031.
* Tighten _is_default_local_cdp to require a discovery-style path so
  ws://127.0.0.1:9222/devtools/browser/<id> is not collapsed to bare
  http://127.0.0.1:9222 (which would lose the path and break the
  connect).
* Move browser.manage into _LONG_HANDLERS so the up-to-10s
  launch-and-retry loop runs on the RPC pool instead of blocking the
  main dispatcher.
* try_launch_chrome_debug uses Windows-appropriate detach kwargs
  (creationflags=DETACHED_PROCESS|CREATE_NEW_PROCESS_GROUP) instead
  of POSIX-only start_new_session=True.
* manual_chrome_debug_command uses subprocess.list2cmdline on
  Windows so the printed instruction is cmd.exe-compatible.
* Mirror host/port validation in cli.py /browser connect so the
  classic CLI never persists an invalid BROWSER_CDP_URL.

cli.py

@@ -6569,6 +6569,19 @@ class HermesCLI:
             connect_parts = cmd.strip().split(None, 2)  # ["/browser", "connect", "ws://..."]
             cdp_url = connect_parts[2].strip() if len(connect_parts) > 2 else _DEFAULT_CDP
             parsed_cdp = urlparse(cdp_url if "://" in cdp_url else f"http://{cdp_url}")
+            try:
+                _port = parsed_cdp.port or (443 if parsed_cdp.scheme in {"https", "wss"} else 80)
+            except ValueError:
+                print()
+                print(f"   ⚠ Invalid port in browser url: {cdp_url}")
+                print()
+                return
+            if not parsed_cdp.hostname:
+                print()
+                print(f"   ⚠ Missing host in browser url: {cdp_url}")
+                print()
+                return
+            _host = parsed_cdp.hostname
             if parsed_cdp.path.startswith("/devtools/browser/"):
                 cdp_url = parsed_cdp.geturl()
             else:
@@ -6588,10 +6601,6 @@ class HermesCLI:
 
             print()
 
-            # Extract port for connectivity checks
-            _host = parsed_cdp.hostname or "127.0.0.1"
-            _port = parsed_cdp.port or (443 if parsed_cdp.scheme in {"https", "wss"} else 80)
-
             # Check if Chrome is already listening on the debug port
             import socket
             _already_open = False