refactor(led-driver): simplify websocket runtime and test layout

tests/test_mdns.py

@@ -15,7 +15,7 @@ Deploy src to the device (including utils.py with mdns_hostname), then from the
 
   mpremote connect PORT run tests/test_mdns.py
 
-If ImportError: copy utils.py from src/ to the device, or rely on the built-in fallback below.
+Copy ``utils.py`` from ``src/`` onto the device if imports fail.
 
 Or with cwd led-driver:
 
@@ -30,26 +30,7 @@ import utime
 from machine import WDT
 
 from settings import Settings
-
-try:
-    from utils import mdns_hostname
-except ImportError:
-
-    def mdns_hostname(settings):
-        """Same as utils.mdns_hostname (fallback if device utils.py is older than host repo)."""
-        raw = settings.get("name") or "led"
-        suffix = []
-        for c in str(raw).lower():
-            o = ord(c)
-            if (48 <= o <= 57) or (97 <= o <= 122):
-                suffix.append(c)
-        s = "".join(suffix)
-        if not s:
-            s = "device"
-        h = "led" + s
-        if len(h) > 32:
-            h = h[:32]
-        return h
+from utils import mdns_hostname
 
 CONNECT_TIMEOUT_S = 45
 # ESP32 MicroPython WDT timeout is capped (typically 10000 ms). Longer blocking work
@@ -213,16 +194,6 @@ def main():
             "Set SELF_LOCAL_GETADDRINFO = True to attempt (may hang)."
         )
 
-    # Optional: built-in mdns module (not present on all ESP32 builds)
-    _dbg(t0, "checking for optional 'mdns' module")
-    try:
-        import mdns  # noqa: F401
-
-        print("Note: 'mdns' module is present; check your port's docs for Server/API.")
-    except ImportError:
-        print("No top-level 'mdns' module; relying on stack mDNS from hostname.")
-    _dbg(t0, "mdns import check done")
-
     if HOLD_S != 0:
         forever = HOLD_S < 0
         _dbg(