feat(led-tool): browser settings editor with Web Serial

Add static editor, host_ports filtering, Flask /editor and REST APIs
for ports and led-cli read/write; document standalone and embedded use.

Co-authored-by: Cursor <cursoragent@cursor.com>

host_ports.py

@@ -0,0 +1,25 @@
+"""Host serial port list filtering for led-tool /ports API."""
+import re
+
+# Exclude /dev/ttyS2 and higher (keep ttyS0, ttyS1; keep ttyACM*, ttyUSB*, etc.)
+_TTYS_HIGH = re.compile(r"^/dev/ttyS([2-9]|[1-9]\d+)$")
+
+
+def include_host_serial_device(device: str) -> bool:
+    return not _TTYS_HIGH.match(device or "")
+
+
+def _is_na(value: str) -> bool:
+    return (value or "").strip().lower() in ("n/a", "na")
+
+
+def include_host_serial_port(port: dict) -> bool:
+    if not include_host_serial_device(port.get("device", "")):
+        return False
+    if _is_na(port.get("description")) or _is_na(port.get("hwid")):
+        return False
+    return True
+
+
+def filter_port_dicts(ports: list) -> list:
+    return [p for p in ports if include_host_serial_port(p)]