Add NFC access control support to Olimex ESP32-C6-EVB driver

- Add get_nfc_status() to retrieve NFC reader state (last UID, access state, auth config)
- Add set_nfc_config() to push NFC access-control config (auth_uid, relay_num, pulse_ms)
- Update API endpoint documentation in module docstring

app/drivers/olimex_esp32_c6_evb/driver.py

@@ -14,6 +14,12 @@ POST /relay/toggle?relay=<n>      → {"state": <new>}
 GET  /relay/status?relay=<n>      → {"state": <bool>}
 GET  /input/status?input=<n>      → {"state": <bool>}
 POST /register?callback_url=<url>                   → {"status": "ok"}
+GET  /nfc/status                                    → {"initialized": bool, "card_present": bool,
+                                                       "last_uid": str, "access_state": str,
+                                                       "auth_uid": str, "relay_num": int,
+                                                       "pulse_ms": int}
+GET  /nfc/config                                    → {"auth_uid": str, "relay_num": int, "pulse_ms": int}
+POST /nfc/config?auth_uid=&relay=&pulse_ms=         → {"status": "ok", ...}
 
 Webhook (board → server)
 ------------------------
@@ -129,7 +135,44 @@ class OlimexESP32C6EVBDriver(BoardDriver):
         url = f"{board.base_url}/register?callback_url={callback_url}"
         ok = _post(url) is not None
         if ok:
-            logger.info("Webhook registered on board '%s' → %s", board.name, callback_url)
+            logger.info("Webhook registered on board '%s' \u2192 %s", board.name, callback_url)
         else:
             logger.warning("Webhook registration failed for board '%s'", board.name)
         return ok
+
+    # ── NFC access control ──────────────────────────────────────────────────────
+
+    def get_nfc_status(self, board: "Board") -> dict | None:
+        """Return current NFC reader status (last UID, access_state, auth config)."""
+        return _get(f"{board.base_url}/nfc/status")
+
+    def set_nfc_config(
+        self,
+        board: "Board",
+        auth_uid: str = "",
+        relay_num: int = 1,
+        pulse_ms: int = 3000,
+    ) -> bool:
+        """Push NFC access-control config to the board.
+
+        auth_uid:  authorized card UID (e.g. "04:AB:CD:EF"); empty = any card opens relay.
+        relay_num: which relay to open on a matching card (1-4).
+        pulse_ms:  how long to hold the relay open in milliseconds (100-60000).
+        """
+        import urllib.parse
+
+        url = (
+            f"{board.base_url}/nfc/config"
+            f"?auth_uid={urllib.parse.quote(auth_uid.upper())}"
+            f"&relay={relay_num}"
+            f"&pulse_ms={pulse_ms}"
+        )
+        result = _post(url)
+        if result:
+            logger.info(
+                "NFC config pushed to board '%s': uid='%s' relay=%d pulse=%dms",
+                board.name, auth_uid, relay_num, pulse_ms,
+            )
+        else:
+            logger.warning("NFC config push failed for board '%s'", board.name)
+        return result is not None