- 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)
scheianu
36de1623c2