handshake-capture-c6 v1.0.4: persist captured BSSIDs, PCAP EAPOL recount

- /cap_bssids.txt append on save; handshakeLoadPersistedBssids after SD mount
- Boot order: SD then load file then first WiFi scan (reds match SD)
- Pre-save walk of in-memory PCAP counting EAPOL-Key frames
- SD_AppendLine / SD_ForEachLine; drop g_sd_ready clear on write fail
- README + MUST_DO updates

Made-with: Cursor

handshake-capture-c6/MUST_DO_IMPROVEMENTS.md

@@ -2,6 +2,25 @@
 
 Full pass over `handshake-capture-c6`: capture logic, SD, UI, display SPI, and main loop. Items below are **simple in concept** (some need careful implementation). Ordered by **severity**.
 
+## Status vs **v1.0.3** (re-review)
+
+| # | Item | Status |
+|---|------|--------|
+| 1 | Serialize shared SPI (LCD + SD) | **Done** — `SPI_Bus_Lock.cpp` recursive mutex; all `LCD_Write*` paths lock; `LCD_addWindow` wraps full flush; `SD_Init` / `SD_WriteFileAtomic` lock + `SPIBus_SetDisplayPaused` so `Timer_Loop` skips LVGL during SD. |
+| 2 | Cap / document `eapol_count` | **Done** — increment only while `eapol_count < HANDSHAKE_EAPOL_FRAMES`; README notes heuristic. |
+| 3 | 2.4 GHz–only sweep | **Done** — `isSupportedCaptureChannel`, `isCaptureable` filters; list shows `5G+` + grey for off-band secure APs; status line `off-band` count. |
+| 4 | Production vs debug serial | **Done** — `HANDSHAKE_DEBUG` (default 0) + `HANDSHAKE_LOGF` / `HANDSHAKE_LOGLN`; boot version line always. |
+| 5 | `USE_SOFTAP` default | **Done** — default `0` in `HandshakeCapture.h`. |
+| 6 | Long SD write / WDT / UI | **Partially** — `yield()` after large write in `SD_WriteFileAtomic`; WDT not explicitly fed (usually OK on Arduino main task). |
+| 7 | Rescan vs `network_index` | **Unchanged** — still no mid-capture rescan; README covers behavior. |
+| 8 | Magic numbers | **Done** — timing + channel range centralized in `HandshakeCapture.h`. |
+
+### Remaining nits (optional follow-ups)
+
+1. **`SD_WriteFileAtomic`:** On failure it sets `g_sd_ready = false` even for a **single-file** error (e.g. disk full, bad filename) while the card may still be mounted. Consider clearing `g_sd_ready` only on errors that imply unmount, or always pair with a defined recovery path.
+2. **`SD_Card.cpp` → `HandshakeCapture.h`:** Include is only for log macros — a tiny `HandshakeLog.h` would remove coupling.
+3. **`LCD_Reset`:** Still toggles CS without the SPI mutex (boot-only; low risk).
+
 ---
 
 ## 1. **Serialize shared SPI (LCD + SD)** — *critical*