Fix SpoolBuddy daemon failing to import hardware drivers

The daemon imports read_tag and scale_diag as bare modules, but they
live in spoolbuddy/scripts/ which isn't on sys.path when systemd runs
the daemon. Added scripts/ to sys.path at startup, resolved relative
to the module file. Also moved the read_tag import inside NFCReader's
try/except (was crashing the daemon instead of skipping gracefully)
and demoted hardware-not-available messages from ERROR to INFO.

spoolbuddy/daemon/nfc_reader.py

@@ -36,7 +36,7 @@ class NFCReader:
             self._ok = True
             logger.info("NFC reader initialized")
         except Exception as e:
-            logger.error("NFC init failed: %s", e)
+            logger.info("NFC not available: %s", e)
 
     @property
     def ok(self) -> bool: