feat: Add v0.4 adaptive sampling — wander detection, auto rate control

On-device CSI wander calculation (coefficient of variation over 50-packet
window). Rate drops to 10 Hz when idle, jumps to 100 Hz on motion with
3s holdoff. EVENT notifications sent to Pi on rate changes. New commands:
ADAPTIVE ON/OFF, THRESHOLD. RATE command disables adaptive mode.
All settings NVS-persisted.

TASKS.md

@@ -2,15 +2,15 @@
 
 **Last Updated:** 2026-02-04
 
-## Current Sprint: v0.4 - Adaptive Sampling
+## Current Sprint: v0.5 - BLE Scanning
 
 ### P0 - Critical
-- [ ] On-device CSI wander calculation (simplified)
-- [ ] Adaptive rate: 10 pkt/s idle → 100 pkt/s on motion
+- [ ] Enable Bluetooth alongside WiFi
+- [ ] Periodic BLE advertisement scanning
 
 ### P1 - Important
-- [ ] Rate change notification to Pi
-- [ ] Tunable motion threshold via UDP command
+- [ ] Report device MAC, RSSI, name via UDP
+- [ ] Pi-side BLE device tracking
 
 ### P2 - Normal
 - [ ] OTA update remaining fleet (muddy-storm, hollow-acorn) via USB
@@ -20,6 +20,17 @@
 - [ ] Document esp-crab dual-antenna capabilities
 - [ ] Document esp-radar console features
 
+## Completed: v0.4 - Adaptive Sampling
+
+- [x] On-device CSI wander calculation (coefficient of variation)
+- [x] Adaptive rate: 10 pkt/s idle (3s holdoff) → 100 pkt/s on motion
+- [x] EVENT notification to Pi on rate change
+- [x] ADAPTIVE ON/OFF command (NVS persisted)
+- [x] THRESHOLD command for tuning sensitivity (NVS persisted)
+- [x] RATE command disables adaptive mode
+- [x] adaptive/motion fields in STATUS reply
+- [x] OTA deployed and verified on amber-maple
+
 ## Completed: v0.3 - OTA Updates
 
 - [x] Dual OTA partition table (`partitions.csv`)
@@ -44,8 +55,6 @@
 - [x] Pi-side: `esp-cmd` CLI tool
 - [x] Pi-side: `esp-fleet` fleet management tool
 - [x] mDNS hostname, watchdog, human-readable uptime
-- [x] Build and flash to device
-- [x] Update CHEATSHEET.md
 
 ## Completed: v0.1 - Documentation
 
@@ -58,8 +67,7 @@
 
 ## Notes
 
-- NVS offset changes with new partition table — first USB flash resets saved config
-- First device must be USB-flashed to switch partition table, subsequent updates via OTA
-- `esp_https_ota` is built into ESP-IDF core — no extra deps needed
-- OTA download ~896 KB on LAN takes ~3-5s, well under 30s watchdog
-- CSI data keeps flowing during OTA download
+- Adaptive threshold varies by environment; 0.001-0.01 is a good starting range
+- NVS keys: `send_rate`, `tx_power`, `adaptive`, `threshold`
+- EVENT packets sent on CSI UDP port when adaptive rate changes
+- OTA download ~904 KB on LAN takes ~3-5s, well under 30s watchdog