SDR++ iak v1.2.2-alpha4

Added

• New CMake-based dependency build system, ported from PrusaSlicer's (written by Tamas Meszaros, @tamasmeszaros): all third-party libraries are now built from source instead of pulling prebuilt binary blobs. This enables native Windows on ARM64 builds and removes the need for the custom Android SDR-kit Docker image.
• Native Windows on ARM64 builds.
• Linux AppImage builds, with isolated config root.
• Radiosonde decoder plugin, merged directly into the iak fork from sdrpp_radiosonde by @dbdexter-dev (Davide Belloli), built on his sondedump decoding library.
• Spots module, merged from sdrpp-spots by @gerner.
• WebSDR view module, based on the KiwiSDR map and waterfall code from SDRPlusPlusBrown by @sannysanoff.
• libcurl integration for HTTPS and secure WebSockets, statically bundled and exported through sdrpp_core.
• KiwiSDR improvements merged from the qrp73/sdr73 forks by @qrp73: server selection by address and port, server band parsing, and map improvements (day/night terminator, country colors, hover tooltips, and a runtime-toggleable marker style).

Changed

• Reworked the WebSocket client for RFC 6455 correctness and hardening (handshake validation, fragmentation, redirect handling, and concurrency/write safety).
• Networking hardening and cleanup across the KiwiSDR and web modules.

Fixed

• QMX on Linux: fixed an exception when enumerating ALSA audio devices (#3).
• Fixed input events leaking through overlapping ImGui windows.
• Fixed flog string conversion for all numeric types supported by to_string.
• Fixed a Debian package build regression where optimization was disabled.

Full Changelog: v1.2.2-alpha3...v1.2.2-alpha4