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/SD_Card.cpp

@@ -69,12 +69,49 @@ bool SD_WriteFileAtomic(const char* path, const uint8_t* data, size_t len) {
     ok = (file.write(data, len) == len);
     file.close();
   }
-  if (!ok) {
-    g_sd_ready = false;
-  }
-
   endSDOperation();
 
   if (len >= 1024) yield();
   return ok;
 }
+
+bool SD_AppendLine(const char* path, const char* line) {
+  if (path == nullptr || line == nullptr) return false;
+  beginSDOperation();
+  bool ok = false;
+  File f = SD.open(path, FILE_APPEND);
+  if (f) {
+    size_t n = strlen(line);
+    ok = (f.write((const uint8_t*)line, n) == n);
+    f.close();
+  }
+  endSDOperation();
+  return ok;
+}
+
+bool SD_ForEachLine(const char* path, SD_LineCallback cb, void* user) {
+  if (path == nullptr || cb == nullptr) return false;
+  beginSDOperation();
+  if (!SD.exists(path)) {
+    endSDOperation();
+    return true;
+  }
+  File f = SD.open(path, FILE_READ);
+  if (!f) {
+    endSDOperation();
+    return false;
+  }
+  char buf[80];
+  while (f.available()) {
+    int n = f.readBytesUntil('\n', buf, (int)sizeof(buf) - 1);
+    if (n < 0) n = 0;
+    buf[n] = '\0';
+    while (n > 0 && (buf[n - 1] == '\r' || buf[n - 1] == ' ')) {
+      buf[--n] = '\0';
+    }
+    if (n > 0) cb(buf, user);
+  }
+  f.close();
+  endSDOperation();
+  return true;
+}