README: document SD card commands, fiwi-telemetry, and telemetry capture workflow

Co-authored-by: Cursor <cursoragent@cursor.com>

README.md

@@ -96,6 +96,11 @@ iperf start
 
 # Check status
 iperf status
+
+# Wi‑Fi telemetry (monitor mode writes to fiwi-telemetry on SD; disconnects WiFi)
+monitor start 6
+sdcard status
+sdcard read fiwi-telemetry
 ```
 
 ## Console Commands
@@ -131,19 +136,29 @@ iperf status
 - `gps status` - Show GPS synchronization status
 
 ### Monitor Mode
-- `monitor start [channel]` - Start WiFi monitor mode
+- `monitor start [channel]` - Start WiFi monitor mode (writes MCS telemetry to `fiwi-telemetry` on SD every 10s)
 - `monitor stop` - Stop monitor mode
 - `monitor channel <channel>` - Set monitor channel
 - `monitor status` - Show monitor status
 
 ### SD Card Commands
-- `sdcard status` - Show CD, mounted, capacity, fiwi-telemetry info
+Telemetry from monitor mode is stored in `fiwi-telemetry` (NDJSON, appended each flush). Use SD commands to inspect or transfer it.
+
+- `sdcard status` - Show CD, mounted, capacity, and fiwi-telemetry file info
 - `sdcard list [path]` - List files (path optional, default root)
+- `sdcard read <file>` - Read and print file (e.g. `sdcard read fiwi-telemetry`)
 - `sdcard write <file> <text>` - Write text to file
-- `sdcard read <file>` - Read and print file
-- `sdcard send <file>` - Stream file over serial (use tools/sdcard_recv.py)
+- `sdcard send <file>` - Stream file over serial (use `tools/sdcard_recv.py`)
 - `sdcard delete <file>` - Delete a file
 
+**Example (telemetry capture):**
+```text
+monitor start 6
+sdcard status
+sdcard list
+sdcard read fiwi-telemetry
+```
+
 For detailed command documentation, see [Quick Reference](doc/QUICK_REFERENCE.md).
 
 ## Mass Deployment