fix(ble): prevent app crash on sendResponse to disconnected central (COLUMBA-6Q)

[sentry]

This PR addresses a NullPointerException that occurs when the BleGattServer attempts to send a GATT response (gattServer?.sendResponse(...)) to a BLE central device that has disconnected during the asynchronous processing of a GATT request (e.g., read/write/descriptor request).

The root cause is an internal RuntimeException thrown by the Android Bluetooth system service when it cannot resolve the connection ID for a disconnected device. This exception is parceled back to the app process, leading to a crash because the sendResponse calls were not wrapped in a try/catch block that handles RuntimeException.

Previous attempts to fix this issue (PR #700, PR #843) misdiagnosed the problem as a Kotlin null-unboxing issue related to the offset parameter, which did not resolve the underlying framework exception.

This fix introduces a safeSendResponse helper function that wraps the gattServer?.sendResponse(...) call in a try/catch(RuntimeException). This prevents the app from crashing by gracefully handling the exception when a central disconnects, logging a warning instead. All existing gattServer?.sendResponse(...) calls in BleGattServer have been updated to use this new safe helper.

Fixes COLUMBA-6Q

[greptile-apps]

Greptile Summary

The PR prevents a framework-originated exception from crashing the Reticulum host process when a BLE central disconnects during GATT request processing.

• Adds a centralized safeSendResponse wrapper that catches and logs RuntimeException.
• Routes characteristic and descriptor read/write responses through the wrapper.

Confidence Score: 5/5

The PR appears safe to merge, with no concrete blocking or independently actionable non-blocking issues identified.

The helper preserves every existing GATT response argument and call condition while preventing the documented disconnected-central framework exception from escaping into the host process.

Important Files Changed

Filename	Overview
rns-host/src/main/kotlin/network/columba/app/rns/host/ble/server/BleGattServer.kt	Centralizes GATT response exception handling and consistently applies it to all response paths without changing response payloads or request branching.

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