- Both olimex_esp32_c6_evb and olimex_esp32_c6_evb_pn532 drivers now
sign every API request with X-Request-Time / X-Request-Sig headers
using HMAC-SHA256(api_secret, METHOD:path:unix_timestamp)
- Board model gains api_secret column (nullable, default None)
- boards.py edit route saves api_secret from form
- edit.html adds API Secret input with cryptographic Generate button
- If api_secret is empty/None, headers are omitted (backward compat)
- New driver: app/drivers/olimex_esp32_c6_evb_pn532/
- Full relay/input control (inherits base behaviour)
- get_nfc_status(), get_nfc_config(), set_nfc_config() methods
- manifest.json with NFC hardware metadata (UEXT1 pins, card standard)
- NFC management routes (boards.py):
- GET /boards/<id>/nfc — management page
- GET /boards/<id>/nfc/status_json — live JSON (polled every 3 s)
- POST /boards/<id>/nfc/config — save auth UID / relay / timeout
- POST /boards/<id>/nfc/enroll — enrol last-seen card with one click
- New template: templates/boards/nfc.html
- Live reader status (PN532 ready, access state, last UID)
- Quick Enroll: present card → Refresh → Enrol in one click
- Manual Settings: type/paste UID, pick relay, set absence timeout
- detail.html: NFC Access Control button shown for pn532 board type
