feat: v0.1.3 — fleet management endpoints

- GET /sensors/<hostname>/config: query sensor STATUS, parse response
- PUT /sensors/<hostname>/config: update rate, power, adaptive, etc.
- POST /sensors/<hostname>/ota: trigger OTA update with URL
- POST /sensors/<hostname>/calibrate: trigger baseline calibration

Added 14 new tests for fleet management endpoints.

TASKS.md

@@ -5,10 +5,10 @@
 ## Current Sprint: v0.1.3 — Fleet Management
 
 ### P1 - High
-- [ ] `GET /api/v1/sensors/<id>/config` — read sensor config
-- [ ] `PUT /api/v1/sensors/<id>/config` — update sensor config
-- [ ] `POST /api/v1/sensors/<id>/ota` — trigger OTA update
-- [ ] `POST /api/v1/sensors/<id>/calibrate` — trigger calibration
+- [x] `GET /api/v1/sensors/<id>/config` — read sensor config
+- [x] `PUT /api/v1/sensors/<id>/config` — update sensor config
+- [x] `POST /api/v1/sensors/<id>/ota` — trigger OTA update
+- [x] `POST /api/v1/sensors/<id>/calibrate` — trigger calibration
 
 ### P2 - Normal
 - [ ] Sensor heartbeat timeout detection