Version 3.1.4-beta7

Iterative beta on top of 3.1.4-beta6. Stops the device from panicking when MQTT Home Assistant Discovery runs out of memory on devices with many status items.

Fix — HA Discovery no longer panics on heap exhaustion

mqttHomeAssistantDiscovery could hit std::bad_alloc inside generateHADiscoveryJson on devices with many status items (134 on a WPU). The exception was uncaught, so the runtime called std::terminate() → abort() → panic → reboot loop. Total free heap could read fine at the point of failure — the heap was just fragmented from the many small std::string / JsonDocument allocations the JSON build does.

Two changes:

• The pre-flight heap check now guards on the largest contiguous free block (heap_caps_get_largest_free_block(MALLOC_CAP_8BIT)) instead of total free. Total free can read fine while contiguous is too small for the allocations the build actually needs.
• The build + publish is wrapped in try { … } catch (const std::bad_alloc&) { … }. If fragmentation tips the heap mid-run after the gate passes, the firmware logs HAD: out of memory during HA Discovery (largest free block now N), skipping and bails instead of taking the whole device down.