v0.4.0

Added

• Zeroconf/mDNS discovery (_uscan._tcp, _uscans._tcp): scanners show up
  under Discovered; the TXT rs resource path is honoured for devices
  that don't serve /eSCL.
• escl_scan.start (with response) and escl_scan.cancel services, plus a
  button.<scanner>_scan_now entity, so automations and stock cards can
  trigger scans without the REST API.
• Translated sensor states and entity names (translation_key), icons.
• Copy to folder option: every finished scan is atomically copied to a
  directory of your choice (Paperless-ngx consume folder), validated against
  allowlist_external_dirs. New file_path / copied_to attributes.
• Diagnostics download (capabilities, scans, redacted entry data).
• Card is available in the dashboard card picker with a visual editor
  (title, sensor entity) and a preview.
• ScannerCapabilities is read at setup: device page shows the real make,
  model and serial; the config entry's unique id is the serial/UUID (survives
  DHCP changes); the scan region is the reported bed size per source (A4 and
  Legal are no longer cropped to Letter); a requested DPI snaps to the nearest
  supported resolution.
• Duplex scanning for Feeder scans on duplex-capable ADFs: duplex in the
  start body and a "scan both sides by default" option.
• Card entity: option; the card also auto-detects a renamed scan sensor.

Fixed

• Creating a job while another client is scanning no longer deletes that
  client's job; the start fails with "scanner busy" instead.
• Per-page ADF scanners that answer 503 between sheets no longer get their
  batch truncated: NextDocument retries while JobInfo reports the job alive.
• Failed/canceled scans are dropped from memory after the retention TTL.

Removed

• pages_total attribute (was never populated).