The committed sdkconfig had CONFIG_ESP_WIFI_CSI_ENABLED disabled, causing
all builds to crash at runtime with "CSI not enabled in menuconfig".
Root cause: sdkconfig.defaults.template existed but ESP-IDF only reads
sdkconfig.defaults (no .template suffix).
Fixes:
- Add sdkconfig.defaults with CONFIG_ESP_WIFI_CSI_ENABLED=y
- Add #error compile guard in csi_collector.c to prevent recurrence
- Fix NVS encryption default (requires eFuse, breaks clean builds)
Verified: Docker build + flash to ESP32-S3 + CSI callbacks confirmed.
Closes#241
Relates to #223, #238, #234, #210, #190
Co-Authored-By: claude-flow <ruv@ruv.net>
