v3.2.0-beta.10 — WiFi watchdog + MQTT reconnect backoff

Reliability fixes from user reports (#13, #20). OTA the attached .bin.

Fixed

• WiFi self-recovers from a wedged stack after long uptime (#13). A soft WiFi.reconnect() couldn't recover a locked-up WiFi stack (dropped at ~79 h, needed a manual power-cycle). New escalating watchdog: >5 min down → full WiFi-stack restart; >30 min down → reboot. A healthy link is never touched.
• MQTT stops hammering an unreachable broker (#20). rc=-2 reconnects now back off exponentially (5 s → 60 s) instead of every 5 s forever, which was wasting the loop + overflowing the publish ring. If you use the Integration/Add-on, just turn MQTT off in Settings.

Pairs with Add-on ≥ 0.41.0 · Integration ≥ 0.18.0.